I replaced the cylinder with an older 807cc Wiseco kit that I used in another motor and a old 1981 KZ 750 head that I got for free from a friend. I did a valve job to the head and milled .032 off the face, right down to the top of the 45 degree angle of the valve. I then ported the head to allow for more flow. I've never ported a head so I thought I'd start with something that was worth very little. I also made a bracket to hold the sprocket cover tight against the cases where the top mounting bolts were missing. Works perfect. After putting 30 quarter mile runs on this motor, I'm very impressed. The bike will run consistent 10.6's @ 122mph
The bike weighs 415 lbs. and I'm 185 lbs. dressed for racing. This stock lower end motor has the stock GPz 750 cams degreed to 105. I've adapted a set of 36 mm CV carbs off of the stock 89/91 GSXR 1100 with K+N filters and Dyno Jet kit. The bike retains the stock igniter box for now, but I have 2 others that I'm ready to try out. The clutch basket has been banded by Falicon Engineering for strength and the stock plates and discs are pushed together by Orient Express springs. The Jardine sidewinder exhaust is wrapped with Thermo Tech header wrap to the end of the collector. I run ND w24 es-u plugs firing the 93 octane pump gas that is reformulated with 10% alcohol for emission sensitive areas.
If you have a KZ 750 motor you could drop in a set of cams from the 83-85 GPz that have .5 mm more lift and more duration. Add a set of GPz 750 carbs that have a jet kit and filters in them and you'd have a great power upgrade. If your tach is driven off the exhaust cam you'll have to fit an electric tach off a later 83 kz or different model bike which I've seen done. Add a Wiseco K 810 piston kit and you'll really be grinning even with the stock carbs. If you decide to put in a 810 kit, get the carbs you're going to use sorted out and working properly as far as jetting goes on your old motor. That way if your too rich while sorting out the carbs you won't have to worry about ruining some thing that you're going to replace (the bore). Putting in the 810 kit will have no effect on your jetting. If it worked good on your old stock 750, it'll work the same on the 810.
The normally aspirated GPz has a 36mm crank and 35mm rod journal bottom end that is of identical size as the GPz 900 and ZX 10 cranks. The Carrillo and Falicon aftermarket rods are still available for this motor that will withstand any abuse. Only the dragracer that has 880 cc or more in this motor running a nitrous system would need this equipment.
For all you owners that do your own valve adjustments, I'm writing about some tricks that I use to get the cams in and out quickly and save some time.
First off, you'll need a new cam cover gasket if the original is still on. You can re-use the rubber half moon end plugs. Use a light coat of silicone or Hylomar on the end plugs for a tight seal. Make sure you scrape the gasket surfaces clean and put the new cam cover gasket on dry except for where the gasket meets the rubber end plugs. You'll also need a torque wrench to tighten the cam cover and cam caps if you remove the cams. A beam type that reads in "inch lbs." is perfect. They're 3/8" drive and I use a CraftsMan for all setting of less than 156 in lbs. (13 ft lbs.). To find "in lbs. " multiply "ft lbs. times 12 = in lbs.". Here's a trick I use on the 1981 and later models that use a wedge type cam chain tensioner. After removing the valve cover and with the pistons all lined up somewhat equally (midway between the stroke.... remove ignition pick up cover on right side and turn engine clockwise to get into this position.), I push down" hard "on the cam chain between both cams forcing the cam chain tensioner back and rolling the intake cam forward. Now that you have a large amount of chain slack between both cams, remove the small 6mm (1.0mm pitch) bolt from the cam chain tensioner (right side) and replace with a bolt that is 1" (or 40mm) long. You have to modify the bolt so that it has some what of a point on the end with a bench grinder or a file. If you have a metric thread file (Snap- On model TFM 7530B ) you can clean up the threads. Or you can thread two nuts onto the bolt before trimming and try to clean and reform the threads after shaping. Now screw this modified bolt tight into the side of the tensioner to lock the push rod down into its compressed position. Now the cams can be removed with the tensioner in place because the tensioner push rod is locked in the backed off position.
Cam cover and cam cap bolts are much faster and easier removed and replaced with an electric screw driver ( "NOT" electric drill). Follow a service manual for checking valve clearances and cam installation. I remove the spark plugs so that the motor can easily be turned over, and cover each spark plug hole opening with a rag so that no debris can fall into the cylinder. Once you have the cams reinstalled, remove the longer 6mm lock bolt in the tensioner and reinstall the short bolt so that the pressure can be applied to the cam chain. Now, Slowly turn the engine forward to check your cam installation as explained in the service manual.
On the latter models, before replacing the cam cover, notice a rubber cushion on the inside of the cam cover that pushes against the cam chain between the cams. If you were to put the cam cover on with the chain pulled taunt between the cams, you'll notice that the rubber cushion will keep the cam cover from resting flatly on the head mating surface. To make the cam cover go on properly, again push down on the cam chain between the cams to get a little bit of slack in the chain. Now if the cover fits against the head mating surface, install, tighten and torque the cover in place. When finished slowly turn the motor clockwise slightly to take up the cam chain slack that remains once the cover has been reinstalled. When you first remove the cam cover the first time to do any service " Take Notice "as to the free play in the cam chain between the cams after the cover is removed and the motor has not been turned over. This free play is the equivalent of 4 degrees of cam timing. YES, the intake cams are off 4 degrees in timing from the factory. For those of you that have slotted their cam sprockets and degreed the cams, the intake cam needs to be set to 109 degrees and will actually be 105 degrees once the cam cover is reinstalled.
Now you know how to spend $2,100 to get a 879.45 cc motor ( 72mm by 54mm).
And YES, I've seen this combination but in the kz 650 motor dragbike of Ms. Monty Fisher of Rockford, IL Runs low 10s and as fast as 9.90 on a very good Day.
As for piston kits, the Wiseco K 810 kit ( 807 cc, 10.25 to 1) is a less costly way to go compared to the Kaw over size pistons. The kit comes complete with wrist pins, keepers and a Cometic graphite head gasket that is the greatest for sealing tight and having absolutely no leaks. The pistons are forged and machined to exact tolerances so that the set is exactly the same. The valve pockets are cut deeper for higher lift cams. As for horse power with this kit, expect to get 83 to 88 at the rear wheel with the stock deck and head heights. The factory manual lists HP at the crank which is always higher in number.
"Horsepower Unlimited" at 310-827-5595 offers many items that'll fit the normally aspirated bike. He has stronger clutch springs for $25 (will fit all Kz,Gpz,Zephyr models) and stronger cam chain tensioner spring for the GPz model ($20) to mention a few.
For the normally aspirated motor
I suggest you buy the Wiseco kit that has 10.25 to 1 pistons and mill .020" off your head and you won't be disappointed. You'll have to slot the cam sprockets and degree the cams to make them right because of the head milling though. If you need more HP than this, I can only suggest that you look at a different bike. It would be much cheaper in the long run "Step 2" would be to add the 810 kit and milling .020" off the head is a must !*!*! Along with that slotting the cam sprockets will have to be done so that the cams can be degreed to their proper position. Stronger clutch springs will also be needed.
The Wiseco kit is superior to the stock components and will run as long or longer. The 'biggest" culprit to longevity and reliability is that the carburation is not overly rich, which is the case in many novices jetting kit "failures".
The Kz 750 and GPz 750 are the same (bore +stroke,valve size, trans gears etc. etc.) other than the cams in the GPz have more duration and .5mm more lift. My present race motor (83 GPz 750) has a 81 Kz 750 head (stock valves and springs) on it with the GPz cams installed. Great combination because the Kz of that year has a smaller combustion chamber than the GPz.
If they offer a copper head gasket don't bother getting it. They weep oil and all the "gasgacinch" in the world won't seal it. Call "Cometic" for a graphite one.
The 1983-85 GPz750 have the hottest cams with .020" (.5 mm) more lift and 16 degrees more duration. Both are interchangeable but if you have a tach that runs off the cam you'll have to switch to a electric tach which is easy to do off a later model bike.
The 82 GPz750 has a combustion chamber volume of 24.9 cc which is very good. The 83-85 GPz750 have chamber volumes of 25.9 cc . The Kz750 H 24.8cc and Kz750 L 25.3 cc. You can easily switch these heads between motors. My present 83 GPz750 has an 81 Kz 750 L head on it.
I'd also recommend milling at least .010" to .020" off the head at the same time to get the full advantage of this piston kit. It will make it noticeably better. I'd also remove the cam sprockets and have them slotted so that the cams can be degreed when reinstalled. They won't be close to what the factory recommends because of chain stretch, new head gasket and milling the head. V&H has a video tape on how to perform this procedure.
When you get the secondary shaft out, take it to the local "well" stocked hardware store and get a long metric bolt that'll fit in the threaded end of the shaft. Get a nut that'll fit on your bolt and some large diameter washers that'll fit over the shaft. Put the washers between the nut and gear you're reinstalling. You now just made yourself a gear pusher. You'll also need a tool to hold the inner clutch basket hub to get the clutch basket off.
Flywheel Clutch Tool pt# 28-288 $27.99 plus shipping from Dennis Kirk (800-328-9280)
Same internal trans gears in all the 750 models. The 83-85 GPz750 has the hottest cams of the bunch. The Zephyr and Kz's share the same cam profiles.
Wiseco had some changes to the top piston ring and gasket configuration in the 1992 through 1994 models that they made. They went from the thick top ring to a thin top ring and then switched back to the thick top ring which they still use today. The Cometic gaskets for the K810 kit prior to mid 1993 are flawed. The cutting dies that they had where flawed (off location) and one metal fire ring protruded into the cylinder slightly. I also recommend that you use factory original valve oil seals when assembling the head as the aftermarket ones don't even compare in sealing quality.
If you do mill the head you need to remove your cam sprockets and have them slotted so that the cams can be moved back (degreed) to the correct position. Most people don't realize how far off the cam settings become when the cam chain stretches much less changing the height of everything. MAKE SURE THAT YOU "LOCKTIGHT" THE CAM SPROCKET BOLTS WHEN RE-INSTALLING THE CAM SPROCKETS. Otherwise they'll back out over time and your nice hot rod motor will be a big box of junk when this happens. First off, your cam settings are almost never what the factory says they are set to because of chain stretch and the difficulty in keeping the deck heights all the same. At best they're usually with in 2 or 3 degrees when new and become possibly better or maybe worse with time depending on which side of the correct reading they're on. Any head milling or aftermarket head gasket will also add to the setting being wrong.
On the Kz 750 model when you remove your valve cover, stop and take a good look at the slack in the chain between both cams. Yes you can take and flop this cam chain up and down with ease when the valve cover is off. Now look at the inside of the valve cover in the area between both cams. There's a big rubber chain cushion that puts a slight downward belly in the cam chain between both cams. You take the cover off and check the valve clearance and by rotating the engine now the slack that was once between both cams is gone. Now you put the valve cover back on and it won't sit flat because it's rocking on the this rubber cushion. Yes, as you screw down the bolts it slowly over rides the cam chain tensioner. Here's the method I use to put the cover back on. I remove the right ignition cover and rotate the motor to where all the pistons would be in the midway position. This means that the 1-4 mark and 2-3 mark are lined up horizontally. Then before I put the valve cover back on, to get some slack in the chain I just push down hard with my thumb on the cam chain between the cam sprockets. This over rides the cam chain tensioner and the intake cam rolls forward and puts some (not to much!) slack in the cam chain. Now the valve cover will sit flat on the head when I re-install the valve cover bolts. After the valve cover bolts are tightened, I slowly rotate the engine forward a quarter turn to remove the slack in the chain and I'm ready to go.
Ok. So where am I going with this ??? Well, when you degree the cams you have the valve cover off and there is no slack in the chain between the cams. After you degree the cams and when you install the valve cover the intake cam rolls forward. What has this done to you intake cam degree setting ?? It's changed it. But how much did it change it by and did it increase or reduce the setting ???????????? Well, lets first talk about were we want to set the cams to. The service manual calls for a lobe center setting of 105 degrees for "all" the 750 models. This is a setting one must calculate given the information listed in the manual. Here's how it's done. Add the open and close settings together .
In the case of the GPz , 38 + 68 = 106 add 180 to this = 286. Now divide by 2 = 143. Now subtract the smaller of the initial cam numbers 143 minus 38 = 105. This setting will be the same for both the intake and exhaust cams.
I've had my cams set from 100 to 110 degrees and the best all around setting is the one that comes from the factory.... 105 degrees. I use this setting in all my motors now.
So now the answer to the cam degree change of the intake cam rolling forward when the valve cover is re-installed. The intake cam will change by 4 degrees. And it'll "DECREASE" the setting. So if you want both cams to be at 105 degrees, you need to set the exhaust cam at 105 degrees and the intake cam at 109 degrees.
For the stock GPz750 and especially for the Wiseco 810 kitted bikes the clutch springs you want are from "Orient Express". When you call them you want to specify that you want their "gold" clutch spring that is 1.5" in length. They'll cost you $25 plus shipping and cod charge that'll bring the cost up another $10. They can be reached on the East Coast at 800-645-6521 or 516-546-5232.
For those of you with the Kz/GPz 750 that are replacing the stock "bore" Kaw head gasket I recommend that you use a Cometic "graphite" head gasket. These gaskets "won't" weep oil like the stock Kaw head gasket, and have proven themselves in many racing applications. These are what come standard with the 810 piston kit from Wiseco. I've used these for years and swear by them. Even Harley Davidson uses the same material in their stock head gaskets for all their motors today. And they don't leak ! Cometic can be reached at 216-974-1077 in Mentor,Ohio. The gasket model you want to order is H0126044G and cut to 66mm Bore size. The price is $38.95 plus $4 for shipping and they take major credit cards. This is cheaper than the stock Kaw gasket.
I've seen in the Yoshimura catalog they sell cams for the GPz 750. Stock valve cover gaskets are "very good" (and no Cometic doesn't offer valve cover gaskets). When replacing the "original" valve cover gasket make sure that the surfaces are squeaky clean. Some people like to put a light coating of grease on the new gasket to keep it from sticking to the mating surfaces and making it easier to reuse. I prefer to put mine on dry and find that if you use a light coat of engine oil instead of grease it'll do the same and be easier to clean. The original half moon rubber end plugs are re-useable. Make sure that you use a silicone sealer on the half moon plugs where they mate to the cylinder head and at the top that contacts the valve cover gasket, otherwise they're likely to leak.
Here's the specs on all my 83-85 GPz750 motors:
I'm always looking to try something that might be less expensive so I ordered a set of racing clutch springs to fit the Kz 900/1000 (pt # 40-0445) from Schnitz Racing Enterprises (800-837-9730) located in Decatur, Indiana . $12.95 for the springs plus $3.50 for shipping put them on my door step for $16.45. These red springs measured 5% shorter than the stock GPz750 springs, but the wire thickness was 25% greater than stock. After I installed them the clutch lever felt slightly stronger than the previous $30 aftermarket spring that I'm using. The difference was noticeable ! The clutch was locked up tight in all gears and there was "never" a hint of clutch spin. I was so impressed with the clutch springs (and the cost!) after this that I called and ordered 3 more sets for the spares pile. These springs will fit all Kz/GPz/Zr 750 clutches. The stock 750 springs measure 48 lbs. @ .950" and the Schnitz "red racing springs" springs are 94 lbs. @ .950" . I find the slight increased clutch pull not to be obnoxious even for city riding with these stronger springs. The price of the springs are $13 plus shipping + handling from Schnitz in the USA. If you or anyone else from out of the USA are interested in these springs let me know and I can send them direct to you at a much reduced cost of shipping.
But here's a new twist that might be a slightly higher compression stock head gasket replacement for the stock Kz/GPz 750 . The factory stock Zephyr 750 head gasket measures .029" thick verses a factory Kaw fiber Kz/GPz 750 head gasket at .039" thick, or a Cometic gasket that measures .041" thick. The .010" reduced thickness would add approximately .2 to the compression of the stock motor. I've not tried this, but there's a good chance that this would work. Now that I've got this old Zephyr head gasket, the next time I tear down a GPz 750 motor I'm going to do some investigating as to the possibilities.
First you should have .020" (.5mm) milled off the head to ensure the best performance and compression from the kit. This figure is on the safe end as I'm removing much more on my street and race motors. You can safely mill the head right into the intake valve seat and up against the 45 degree angle of the seat. Don't mill into the 45 degree angle. This is somewhere in the area of .032" to .035" of material removed. I'd take a minimum of .020" off and .025" would be even better for the 810 kitted motors. I've have four 810 kitted motors with over .030 milled off the head. Three GPz750 heads and one 81 Kz750 head. If you don't mill at least .020" of the head for the 810 kitted motor you'll be disappointed with the results. Although the valve angle is the same, the 750 has larger valves (33mm intake 29mm exhaust) than the 650 so there might be a problem with clearance. The combustion chamber volume of the 83 GPz750 head is 25.9 mL The 80-82 Kz750 or 83 and later H model heads have a combustion volume of 24.8 mL . The Kz and GPz heads use the exact same valves and springs. The early model 750 heads have the cam tach drive feature also.
From: Allan.Webster@West.Boeing.com (Webster, Allan S)
I emailed you a while ago about my GPZ750 for road racing. Anyhow, I guess the actual horsepower is closer to 100, or maybe 110 This is in the area of .030" to .035" removed from the head surface. Lower than 93 octane fuel can be used, but you'll need a 35 degree total advance ignitor from the 1000R Ninja and a jet kit to make not ping. If you shave the head, you'll also need to degree the cams.
I've read several articles written by people like Warren Johnson about valve trains. Matching the correct spring to the valve lift will produce the most HP. A spring that is too weak will promote excessive valve bounce and valve float, while a spring that is too stiff will rob the motor of horsepower to compress it. I agree that checking the stock spring against the factory specs is the best thing to do. I've often thought of trying some stronger valve springs and perhaps I will someday. If I do it'll be a set of APE springs made for cams with up to .460" of lift. Schnitz Racing (800-837-9730) offers a complete set of APE valve springs to fit the Kz650 through 1100 2 valve motors ( part # VS 900K) for $46 plus shipping. Here's some advice about how to properly set the cam timing on a GPz750 motor. The 83-85 GPz750 valve cover has a rubber cushion that depresses the valve chain in the area between the intake and exhaust cam sprockets. With the valve cover installed, the rubber cushion moves the intake camshaft forward 4 degrees. When one degrees the cams, the valve cover is off. This means that the cam chain is tight between the intake and exhaust cams. With the valve cover installed, your 105 degree intake cam setting is now actually 101 degrees! So what you need to do is degree the intake camshaft to 109 degrees, and when the valve cover is reinstalled it'll roll the intake cam 4 degrees forward to 105 degrees. For those of you that question what I wrote is true, try this. Before removing the valve cover turn the motor crankshaft forward slightly by hand with a ratchet. Now remove the valve cover. Take a "good" look at the slop in the cam chain between the intake and exhaust cam sprockets. Take and move the cam chain up and down. With a degree wheel on the crank, you'll measure the crankshaft move 4 degrees to make the cam chain tight between the cam sprockets. This is the same condition that exists when you are degreeing the cams.
I added an oil temperature gauge (VDO) about a month ago and it works great but the MOD was a bit tricky. I got a sensor to mount on the engine and there are 2 plugs on each side of the motor (lower front corners) that can be removed and a car sensor can be added. The problem is that the plug is 18mm and the largest sensor is 14mm X 1.25 thread (it might be 1.50 but I threaded it with a 1.25 tap and its working fine. The sensor is about $12 and the gauge around $29 (I got my gauge at a flee market for $6) My bike took REALLY well to a Dynojet kit, K&N internal filter and new pipe. External filters were avoided due to their sensitivity to water, and I ride a lot in the rain. They also are loud enough to wake the dead (intake noise). I originally installed a Yoshimura Supersport pipe intended for the street. It was much lighter than the stocker (I could feel the difference in handling) and the bike made much more power, especially on top (seat of the pants measurement). It also allowed retention of the center stand and access to oil drain and filter. Unfortunately, it was louder than a rabid banshee, so I removed it and installed a new Hindle Stealth. According to Sport Rider tests, it was even 3 dB quieter than the new "quiet" SS2R Vance and Hines and makes as much power (if not more) than all other after market pipes they tested (they tested them properly rejetted for).
I've found that it makes noticeably more power in the midrange than the Yosh, and is VERY quiet for an aftermarket pipe. It's more than socially acceptable. Fitting it to the bike took 1/2 an hour. Unfortunately, it restricts oil filter access and involves muscling the headers to get it out. This means that muffler compound must be reapplied at the header/collector joint each time I change the filter. I also had to make an aluminum hanger bracket (the provided one is too short) out of a 2-3" long, 1" wide piece of 1/8th" thick aluminum ($2) and used it as an extension piece from the ring clamp around the pipe to the mounting location on the frame. If this isn't done, the pipe would have to be moved into a position which causes hassles with the passenger pegs (the passenger pegs would dent the top of the pipe). I also bought hot water tap washers as vibration isolators at the frame, and used nice hex head machine bolts to hold it in place.
This all sounds like a pain in the ass, and it is, but was well worth the trouble IMO. It looks great, sounds fantastic, and makes great power. The throttle response is much improved over stock or with the Yosh, power is improved anywhere (realize that I also added the Dyno-jet kit) and the center stand was retained. The pipe costs around $450 Canadian through Hindle. If anyone tells you that a pipe kit and rejet do not add horsepower, than you are talking to someone who never rode a 10 year old bike. For more serious modding, I'll pull from two sources. The following engine info is based on GPz750 hop up articles from old issues of Cycle Canada ('84) and Cycle ('85, Joe Minton). To get any more power from the engine, freshen it up with a 3 (or 5) angle valve job and shave the head to recommended minimum height. The engine can take it. That would be a good time to ensure there's no valve guide slop and to replace the valve seals to ensure no smoking on trailing throttle. I'd be careful about head shaving AND adding a big bore kit as the big bore pistons already up the compression. Shaving the head may lead to detonation with the new pistons, or worse, crown and valve contact (can you say kablooey?). There's also an 810 Wiseco kit (I think 850 kits too) to pump the engine out even further through a 3mm overbore. If you ever decide to do any ring/cylinder work, it's worth looking into these kits. Of course, you have to re-jet, but taken in conjunction with the new air filter and pipe, the increase in midrange and top end is apparently 10 ponies or more. The Wiseco gasket kit is aprox 1/2 to 2/3 the OEM price.
Adding a new carb bank (40mm flat slides are available) adds many a top-end pony, but costs too much to bother with on this bike IMO and will no doubt weaken the already limp midrange. The hop up articles threw in new cams from Mega Cycle and advanced the engine a couple of degrees (107 deg from the stock 105). I won't bother as the bike seriously lacks midrange already and the cams are biased towards top end. If you do any head work, install a GPz750 Turbo gasket kit. It's the same price as the standard, and it's stronger. Aftermarket gasket kits are available and are much much cheaper than OEM. A larger oil cooler was available from Lockhart. If you really pump up the engine, look into this. Even relatively stock, I've had the bike almost overheat in traffic jams on hot summer days. An Accel Supercoil kit has been reported to improve midrange and throttle response on the GPz.
Seeing as how this is a race bike, I recommend that you use a "Cometic"(800-752-9850 in Mentor,Ohio) graphite head gasket model #H0126044G cut with 66mm bores. About $50 delivered. This head gasket positively will not leak. The replacement stock Kz/GPz Kaw head gaskets are very prone to leaking and especially when used in racing applications. The Cometic gasket measures the same thickness as the stock head gasket.
Yes, the Wisco kits include a Cometic graphite head gasket
The stock valve clearances apply with the 810 kit.
There are 2 different types of automatic cam-chain tensioner used on old Kawasakis, which I know as the ball-race and the cross-wedge types.
The ball-race tensioners work very well when new, but the balls do eventually wear grooves in the push rod and in the tensioner casing which means that the precise locking no longer works and it backs out allowing the chain to rattle. When this happens, there is no alternative to buying a complete new tensioner. :-( You could try stripping and cleaning it just in case it helps, but they're generally very reliable until they wear out. The first one on my SR650 went at around 30k miles and its replacement was still ok 20k miles later when everything else in the engine was completely worn out after too many enjoyable Sunday thrashes and it was replaced by a Z750 engine.
However, on the plus side, there's better news if you've one of the newer cross-wedge type tensioners (which I think's fitted to most 750s and other big Zeds). :-) When these wear, you end up with ugly grooves and ridges on the push-rod and on the cross-wedge where the two contacting faces meet. When this happens, the cross-wedge either doesn't move to take up the slack to lock the push-rod in place or gets pushed back out, again allowing the cam chain to rattle. I've found that if you dismantle the tensioner and use progressively finer (down to 1200 grade) wet and dry paper on a hard, flat surface and finish off with a polishing compound you can smooth the two faces down to a near-mirror finish (or certainly enough to get rid of the grooves and ridges which cause it to stick). Then you clean them very carefully (to get rid of all the abrasive particles) and reassemble with decent grease on the two faces. You can check that it works before putting it back on the bike by pushing the rod in and out with your hand whilst keeping pressure on the cross wedge with a finger and making sure that it doesn't stick or jump anywhere. If you do this, you'll get many thousands of extra miles of use out of it. I did this on my 750 a few years ago and have had no problems since, in a combination of town-riding and Sunday afternoon, flat-out blasting through the twisties.
As an aside, for those of you who don't mind getting your hands dirty once in a while and want to have absolute confidence in their tensioner, I've heard that a manual tensioner from an early Z250 will fit straight in. I had one of these on my first "big bike", an old 1980 Z250, and in the 30k miles I thrashed it around I used to check and adjust the tensioner every few thousand miles and never had a single problem with it. You can also get manual tensioners from tuning and aftermarket goodies shops as well, which I shall probably try on the 11 when I want to do something but can't think of what else to tune up on it.
Hope this is of some use to you.
Joe Smith, Senior Engineer, GenRad ADS
If you look at the identity numbers on your igniter box , they should read 21119-1069. This stock igniter box delivers 40 degrees full advance @ 3,600 rpm. I am running a igniter box # 21119-1165 from a 1986/87 1000R Ninja in my street bike for the past 5 years. This box plugs right into the stock terminals and has 35 degrees full advance @ 3,500 rpm and a rpm limiter at 10,700 rpm. The slight decrease in advance makes the bike more linear through out the rpm range and allows for the same performance as the stock igniter. The stock valve train will easily run to 11,000 rpm and this limiter (10,700)
will assure the well being of the motor. An igniter that I've been looking for but haven't tried (1986 - 600 Ninja igniter # 21119-1056) has 40 degrees full advance @ 10,000 and a rpm limiter at 11,100. This limiter could provide more low and mid range response because of it's curve. These igniters can be bought through motorcycle salvage yards but I recommend comparison shopping a "MotorCycle Shopper" magazine where these boxes can be had for under $75 from people parting bikes.
2. Cope Racing ( Dave Shultzs motor builder) lists the best full advance setting for the 2 valve Kaw motors at 34 to 37 degrees
3. With a 35 degree box in my dragbike, it'll 60 foot .015 to .020 seconds faster than the stock 40 degree box. This I have documented in my racing database files. My bike leaves the starting line using a 2-step at between 6,600 to 7,800 depending on track conditions.
I have had many boot ends that read "open" but will still fire the plug as the charge will jump the gap in the boot. NGK # LB 05 F stock replacement ends can be had from Dennis Kirk for $2.25 ea.
The stock Kaw coils are some of the best around, but ACCEL offers after market coils that will increase spark by over 20%. The coil kits come with the tools and 2k ohm per foot wire to make the correct lengths to fit your bike. I've had these coils on the street bike and drag bike for many years.
Instead of using the Accel wires provided in the kit, I recently bought a set of Accel 8.8 300+ race wires that have 150 ohms per foot of resistance. I ordered kit # 7031 (Jegs mail order $55) V8 universal fit, 90 degree plug boots with HEI distributor. The distributor boot ends plug right into the Accel coils. I was able to make up 4 complete sets of wires with the old ends I previously had. These wires provide the hottest possible spark while offering excellent protection to noise interference. The Accel 300+ wires are 8mm and need to have the insulation trimmed to fit in the stock coil openings. They too will work fine with the stock coils.
I run ND w24 es-u plugs firing the 93 octane pump gas that is reformulated with 10% alcohol for emission sensitive areas. 3. Less total ignition advance (35 degrees instead of 40) for the lower rpm range enhancement that will help the upper rpm range also. Here's how to quickly check for this problem and cure forever. Your clutch lever has a switch located at the underside that has a 3 wire female plug attached to it. If you unplug the switch and run a jumper wire joining the two outside openings of the female plug together you will have "bypassed" the side stand and starting "in" gear circuit completely. Tape the wire to the female plug and take the bike for a test ride. If this cures your high rpm missing problems here's the cheapest and best fix. Reconnect the female plug to your clutch lever as this circuit will keep you from being able to start your bike while in gear with the lever in the out position. A great system to have. Remove the side stand switch completely and plug the ends (1 male, 1 female) from the harness together bypassing this system completely. You'll be able to ride with the side stand in the down position (by mistake) and your side stand warning light will no longer function because of this modification. The "elimination" of this component for the Kaws is a must for trouble free high rpm performance.
If they're Accel then the part number on the coil should be 140403 and can have a suffix of S on some models. Motorcycle Accessory Warehouse (800-241-2222) has coils for $100 plus S/H Dennis Kirk (800-328-9280) $124 delivered You "DO NOT" want the CDI model as this is the "WRONG" application. You want the model for points and/or inductive pick-up or otherwise know as the "non-cdi" and I'd buy the kit that includes everything. The coils are approx. the same size and the mounting kit works. You just need to be a little creative.
I run the Accel 300+ race wires that are offered for race cars. These wires have only 150 ohms per foot of resistance. Muzzy had moved the ignition timing around so there was only 30 degrees total advance because they said they want to be able to run on pump gas. The 30 degree ignition timing that the "claimed" 11.1 to 1pistons ran would be somewhat lower than needed today even with the pump fuels we use. I do believe that the reduced timing does enhance performance and the 32-34 degree settings are what's popular for the Kz 900/1000 (also 2 valve) among the drag racers of these motors.
The Wiseco 810 kit with .020" milled off the head will run with the stock 40 degree advance and not ping excessively in hot weather. The 35 degree ignitor box from the 86-87 1000R (rev limiter equipped and used in my street bike) or 84-86 900 Ninja (no rev limiter and used in my race bike) will make the midrange better (linear) and produces slightly faster times (.05) in the racebike. (I'll post the ignitor box #'s upon request and yes they plug right into the 83-85 GPz750 models).
The best ignition set up is that of the Zephyr. It has the most linear advance that finally peaks out at 35 degrees when 7,000 rpm is reached. This ignition is unique to the Zephyr and wont fit the older bikes without a system change over that would require a single plate ignition trigger and ignitor like those on the late model Kaws. the GPz 750 "is" inductive which is the same as points and is "not" CDI. Inductive or point type coils will have a measured resistance of approximately 3 ohms. The CDI type coils will measure 1.5 ohms across the primary side ( this is where the positive and negative leads are attached to the coil). Even if you end up with a CDI coil you can turn it into a inductive type by adding a 1.5 ohm resister to the primary side making the total ohmic value 3 ohms. This is what MSD does with their coils to run them on either system. The 2 valve motor will make the most HP by using an advance in the 32 to 37 degree range. I base this on the facts and figures I've seen from dyno sheets on the 2 valve drag racing motors that can run as high as 11,500 to 12,000 rpm. I've heard the Pro Stock motors of Shultz + Star racing run as high as 13,000 rpm.
The 1984-85 900 Ninja has a 35 degree box with no rpm limiter (box # 21119-1111) that I use in the race bike. The 86-87 1000R Ninja has the 35 degree box "with" the rpm limiter at 10,600 rpm ( box # 21119-1165 ) that I use in the street bike. THESE BOXES WILL ONLY FIT IN THE 83-85 GPz750 models and work the same other than one having the limiter.
The 86-87 1000R Ninja boxes can be made to fit the 82 and "earlier" Kz/GPz750. But you'll also need to get the large "single" plug with 6" of wire attached that mates with this box.
> Was able to pick up (10 bucks) a pair of ignition coils from a 95 or 96 ZX6R.
Yes these are inductive type (points also) triggering system coils and will work on all the Kz/GPz 650/750 and are at the top of my list for the "best" budget replacement. Make sure you put a meter to the plug wires and end caps to make sure the resistance doesn't exceed 5k ohms.
The Jardine sidewinder exhaust is wrapped with Thermo Tech header wrap to the end of the collector. The GPz 750 and other bikes have "vacuum" operated fuel petcocks. When the motor is running vacuum keeps the petcock plunger in the open position so fuel can flow to the carburetors. In about 5 years time, the plunger (may) become stuck in the open position, thereby never shutting off the fuel. For people like me that trailer their bikes a lot, the fuel will fill the motor if left to the on state, as the bouncing of the fuel floats while trailering will let the fuel pass through the float valve needle flooding and overflowing the carbs. To fix this problem I first disconnected and plugged the vacuum connections to the petcock. I then removed the back side of the petcock housing that contained the plunger and plunger spring. I cleaned and lubricated the plunger and housing with WD-40. I took the spring and stretched it to twice its normal length and reinstalled. Now I manually work the petcock by leaving it in the "prime" position during running or the "on" or "reserve" position that is actually off now. This way I can run the majority of the fuel out of the carbs when I so desire. This is one system I can (and will) do without. The earlier heads also had smaller diameter exhaust pipe mounting studs than the later models. Be aware that putting in hot aftermarket cams can (might) affect the signals sent to CV carbs and make tuning them very hard.
STAINTUNE- made in Australia out of stainless steel. 4 into 2, or 4 into 1, retains standard features (center stand etc.). Excellent quality, performance, looks etc. but expensive. LASER-(made by JAMA)- made in Holland. There's three brands made by the same company: LASER- 4-1 steel and aluminum/carbon sports type exhausts; Here's a rule of thumb for pilot jet sizes. If your pilot screws are set to 1/2 turn or less then going to the next smaller size pilot jet is best ( from 35 you'd go to 32.5) If your pilot screws are 4 turns or more then going to the next larger size is best (from 35 you'd go to 37.5) If you switch, the "oval" type filters (K+N or V+H) is what you'll want and a DynoJet stage 3 kit to make the jetting work right.... there is "no" other way. Been there and done it more times than I care to write about with the 83-85 GPz750 stock carbs. I put the 810 kit in my 1984 model … the suggestion was to go to GSXR 1100 carbs (34 mm) with a stage III kit (you will lose the air box) I took a long time to get them right (better to get rebuilt set to start) but the power difference is day and night. I mounted 2 very dressy extensions off the side covers to protect when riding in the rain (ran fine during FLOYD's down pours). I still have a little sputtering in the throttle when I first start to turn the throttle about 1/2 inch but past that point she is as smooth as glass and hard to hold on to. She is also running a little rich (25 mpg) which will be fixed when I have the rear shock put on this week.
Mark: On the racebike they make 95 HP at the rear wheel with my 36mm Slingshots and sidewinder exhaust. With the stock carbs and aftermarket street exhaust they make an easy 80 HP or more This is what I did when I installed my DynoJet kit... Pull all the hoses off the breather tubes on the cam cover and connect a short rubber hose from one breather tube to the other. Simple as that. I was concerned that there would be some kind of pressure build-up, but my mechanic said not to worry about it. And it never caused a problem. With my DynoJet kit came individual K&N filters, so the stock breather box went into the trash (should have kept it). The breather hose that went from the top of the crankcase into the airbox then was shortened and went into a small K&N oil breather filter. I zip-tied the hose to the frame above the swingarm so it wouldn't flop around. And of course, all the breather hardware that was left over, under the tank, went into the trash as well. .....................................................................
The crankcase venting into the stock intake air box has NO effect on your jetting or carburation. And the same can be said when you install a DynoJet Stage 3 Kit. Also, you can either leave the air induction system installed or remove it when adding the DynoJet kit. To disable the air induction, just run a hose between the two inlets on the top of the valve cover so that they're connected together. Although my race and street bike both run DynoJet Stage 3 Kits, the air induction system has been retained and is in working order. I just use a simple foam air filter at the intake on the induction hose. I won't elaborate why this system is still in place. My ET's at the track says it all.
An incredibly cheap (free) mod is turning the eccentric chain adjusters upside down. This decreases rake/trail and quickens steering by raising the back of the bike. This works wonders if the drive train is stock and with the fairing retained. The bike steers with more control without sacrificing stability. Telefix and ATK made fork braces for the GPz, and the Telefix is still available new (advertised for $82 out of the back of Motorcyclist, mail order). I called salvage yards and scooped a used ATK for $75 Canadian (they want about $140 for a new one here.) I've talked to race chassis builders who used to work on the GPz, and they highly recommended one. Good enough for me. The ATK is very well built out of aluminum and it looks great. It's available in aluminum or black colours. Be aware that there are two versions around, the standard one, plus one with shimming to beef up the thickness of the brace at the mounting areas and add clearance. The GPz requires a shimmed version to clear the fender. Make sure you follow the shake down procedure I previously recommended when installing one so that it doesn't bind. I've yet to look into a steering damper, but Lockhart still sells one for the Turbo which should work in a pinch. Maintaining tapered roller steering head bearings in good shape is a gimmee.
Dennis Kirk sells replacement front fenders specifically for the GPz750. They offer a more aggressive look that fits the bike. The Turbo also came out with a different fender that fits and updates the look. Targa and others made fairing lowers, or the Turbo lowers are available from Kawi. For footpegs, Raask supposedly makes lighter units retain the passenger set up. They may still be available from Spec II. For race applications, a common trick was to triangulate the frame. Look at old pictures of Wayne Rainey's GPz750 running AMA, and you'll notice triangulation running across the frame from front downtubes to the back of the top rails, next to the cylinder banks. Frame spars can also be welded between the top two rails, under the tank. All this is no doubt costly but it greatly enhances frame rigidity. The major drawback is that it reduces engine servicing ease by wiping out clearance and making access to the engine more difficult. I've opted to forego this one.
A racer from Rochester New York showed me his frame mods which he arrived at with the help of some GM engineer friends. He said the best frame mod was adding a cross member above the swingarm pivot between the frame rails, and another one up the rear frame rail just before they bend to go over the engine. He said it made a hell of a difference. Antidive on the GPz750 works in the following way: Brake pressure works a piston in the anti dive unit that closes off a fork oil passage way from the forks. This deprives the fork oil from getting at some holes in the damper rod. The result is drastically increased compression damping under braking. The anti dive is not particularly effective on the GPz750. Removing it made a major improvement. Why is it so bad? The increase in compression damping upon braking makes the front end so hard that it has trouble tracking over bumps, especially with the Progressive fork springs installed. I was only using up half my fork travel and the front would slide under hard braking since the weight was not being properly transferred to the front tire. Note that improper fork bushing tolerance makes the anti-dive less effective as oil seeps through the bushings instead of through the damping rod. If your bushings are sloppy, your anti dive may be partially disabled already.
Properly removing the anti-dive is pretty easy. I'd caution against it though unless you have progressive springs installed. The _stock fork springs may not be up to the task without the added compression damping. Install Progressive springs first. The fix involves removing the entire front line system except for the anti dive units. All the mounting junctions and blocks can come off too.
Next, replace the now removed brake line system with steel braided lines right from the master cylinder to the calipers. One of the double banjo bolts that was on the upper slider junction block can be used at the master cylinder. About 5' of line will be needed. Be VERY careful installing the fittings, they will easily leak if the ferrules are improperly installed.
One benefit of the steel braided system is a cleaner line system which will remove a lot of dead space present in the old complicated set up where air could have collected and made the brakes spongy. It also removes some dead weight and greatly cleans up the look of the front end. If you can't afford steel braided lines, you can still remove the anti-dive by removing the steel fluid tube from the junction on the slider to the anti dive unit. Block up the hole left by the pipe at the junction block with a 12 mm fine thread bolt. On the anti-dive unit, block off the hole left by the pipe with a 12mm fine thread bolt. This will ensure that the piston doesn't seize up from rust or crud. Don't forget, the anti dive unit can still affect the damping, so keep it's internals protected from the elements with that bolt. Note: You can't simply remove the anti-dive unit and plug up the hole on the forks as the result will be the forks feeling like they are at constant anti-dive maximum: i.e. outrageously high compression damping. Even removing the top 1/2 of the anti dive unit is impossible as it will expose the piston to the surrounding environment. The only way to remove all this is to machine a small aluminum block with the passage way in it that bolts on in the anti dive's place. This will lower the unsprung weight, but is too big a pain in the ass to bother with. The absolute best investment you can make is to the suspension. I went to a set of Progressive front springs, and it felt like I bought a new bike: much more control in bumpy sweepers, no bobbing or weaving from the front. They are worth 3 times the price. You can play with fork oil weight too. I prefer 15w with the Progressives, 10w is the minimum I'd go to. 15W provides a compliant enough ride without being harsh IMO. Because of the springs, I run no air pressure in the front forks. Excess air pressure would just create binding and the springs are progressive enough to not need air assist. Depending upon your weight, this may vary.
Some people recommend ATF instead of fork oil, but realize that ATF is not standardized for weight and cans out of the same crate can have values differing from 5W to 15W. It's cheaper, but it's a crap shoot. It's also a good idea to remove the stiction in the front end. The technique I used was out of 10 year old bike mags, and it worked perfectly. Remove the front fender, loosen the fork pinch bolts at the top triple clamp, the front axle nut, the axle pinch bolt on the lower fork and the steering head bolt (don't worry, the lower nuts under the triple clamp set the steering head bearings). Grab the front brake lever, take the bike off the stand and pump the forks up and down hard for 30 seconds. Have a friend hold the bike upright, and tighten the steering head bolt followed by the top triple clamp pinch bolts. Do the shake down again then tighten the axle nut followed by the fork lower pinch bolt. Reinstall the fender, making sure it does not bind but slips right on. This technique removed a lot of stiction in my forks (just tried it this weekend).
The next major improvement I made in damping control was removing the anti-dive. This is covered separately in the next section. Fox no longer makes shocks for the bike. Nor do Kohni or Progressive. Only Works will make one, the Ultimate, an aluminum bodied shock with remote reservoir and compression/ rebound/preload adjustment capability. Cost is $530 US, and wait is "2 weeks to 2 months". You may be able to get it cheaper through a dealer. I installed a used Fox and it *transformed* the bike. Much more stable, much more comfortable, much more controlled on hard throttle transitions. Probably the best chassis mod you can make. If you keep the stock shock, just keep the air pressure monitored. The stock gearing revs 6000 rpm at an indicated 140 km/h (real 130 km/h as the speedo is overly optimistic with an ME33 front tire). I've done some calculations and found that upping the rear tooth count by 2 brings the revs at indicated 140 up to 6300 and upping three teeth brings it up to about 6500. Top speed (and it will pull it) will drop from a stock (real speed, not indicated) around 136 mph, to 130 mph with two teeth to 125 with three teeth. IMPORTANT: For every added tooth, add 1/2 a link to your chain length calculation: the sprocket is round and the chain only contacts 1/2 of it. The center bolts do not change. This may not be intuitively obvious, but it comes clear when you draw it out. Link numbers which are odd (109, 111 etc) require a special link. It may be wise to go up to the next biggest size, then remove two links down the road as the chain begins to wear and lengthen.
As for paint, the "original factory color" (firecracker red) in spray or pencil be had from Color Rite @ 800-736-7980 if you need the color to be exact.
> Race Tech's "Emulators" on there GPz's > ??
If so gimme a shout on yer opinions. Also if you use them, do you use > them alone, or can ya use Progressive Springs spring kit with them. I > noticed that they list Kawi's EX 500 in the same part list as the GPz
so > does anyone know if these forks are the same or just the same fork tube > diameter.
I've not installed them, but I've gathered some information:
You can use the stock or aftermarket springs.
These valves replace the drilled damper rod in the stock forks. Instead of drilled-to-size orifices of the stock damper rod; modified forks with valves have an adjustable set of spring controlled "floppy washers". Now, compression and rebound damping can be adjusted separately: Fork oil weight will vary compression damping and twisting the little screw on the new valve adjusts rebound damping. IMO, setting up the modified forks may approach Mark's description of carb jetting: Rocket science. : )
Most of what I'm passing along here was picked up reading posts on road racing oriented e-mail lists. (Generally, a thumbs-up on the valves from these sources) Apparently, the kits come with some well done directions, which should be followed carefully and exactly. Installation is not difficult. Instructions will include some base line fork oil weight and valve setting info.
The forks on the GPz750 and the EX500 are not the same. The later model, '93 & later ?, EX500 (with the larger, 17" dia. wheels) has the same fork tube diameter as the GPz. The fork valve "emulators" have fork tube inside diameter as a critical dimension. The Kaws all use many of the same pads between models. For example here's "some" of what fits the 83-85 GPz750 250 Ninja 86-87 550 GPz 84-85 700 Kz 84 700 LTD+Vulcan 84-85 750 Vulcan 86-96 900 Ninja 84-86 1000R Ninja 86-87 1100 LTD+GPz 84-85 1300 Voyager 83-88 1200 Voyager 86-96 Second, RaceTech _really_ likes straight rate springs over progressives.
Third, you _need_ a very specific tool to pull the compression rod. And, the GoldValves require drilling additional holes (in the compression rod) for oil flow. also, there recommendation is constant rate/20w and I would assume no air. Here is a link to a fellow in eastern USA that will fit bronze solid bushings to the swinging arm instead of the needle bearings. You'll have to ship him the arm and the swing arm bolt/pivot. I believe the cost is about $80US, plus shipping. If I were going to replace the bearings on my GPz, I'd go this route. I will be using him for my T500 vintage roadracer project. The custom machine-to-fit results in closer tolerances and the solid bearings give greater area to absorb the loads compared to the needles. URL: http://www.freeyellow.com/members/batwings/best.html
I've no financial connections or other personal interest in his services. . For any that are interested, the zxr750 j2 front end goes in to the gpz 750 frame with little effort (head needs to be machined down by 8mm and = checked for true) and the zx6r backend bolts straight in, all it needed was matching for bearing sizes. The bike sits lower now but the steering geometry promises an exciting ride.
Mike Chestnut of Horsepower Unlimited (301-827-5595 California) offers a GSXR shock that has been modified (mounting) to fit the GPz750 Turbo (same as GPz) . He revalves the shock and set you up with the proper spring. The shock includes a remote reservoir and is fully adjustable. The shock is in the $500 range ... the same as if you were dealing with Fox. I'd call him for more specifics.
Today Fox no longer offers this shock for the 83-85 GPz 750. Horsepower Unlimited (310-827-5595)offers a shock to fit the GPz750. It's a GSXR shock that has been completely rebuilt, has a "gold valve emulator" installed and modified to fit the GPz mountings. This remote reservoir fully adjustable shock is set up with the correct spring for your ride weight and type of riding you do. If you find the shock too stiff or soft they'll rework the shock and spring to make it right for the first 30 days. The cost is $400-450 for this shock. Many will think that this is "too expensive" but IMHO I find this to be a very good deal if one plans to keep the bike for more years to come. They even offer a rebuild service for the shock when it's needed for $125 (same as I pay Fox for this service). I called Mike at Horsepower Unlimited and asked him about his gsxr retrofits: the basic story is that he doesn't build up the shocks himself, but has a friend who fits gold valve emulators and will set up the settings per weight and riding style for about $400-450 with about a 3 week order time. I've talked to Horsepower Unlimited on the shock they offer and for the same price you can get a rear shock from "Works" in Canoga Park, CA (818-701-1010) that is a much better deal imho. The HP Unlimited shock has the mounting brackets changed to fit the GPz750. Works Shocks specializes in only this product and for $400 they can offer you a shock to fit the GPz750 and for $470 they can add the remote reservoir which is what I'd be getting if I were ordering one for myself. The shock is set up for your riding weight and application (street/roadrace). Works has been building shocks since 1973 and is well known and respected in the industry called various salvage yards and came up with a shock from a 90 gsxr 1100 with remote res/ and the damn thing bolted up, almost. The mountings need to be modified slightly, but it's a basic fit, no problem.
>What were the torque settings you used?
As I mentioned, I did it by trial and error. I'd tighten the bearing adjuster and torque the nut over the triple clamps to spec. The bearing would be adjusted till the forks would just slowly flop over on its own weight with the bike on the center stand and the front tire off the ground (you'd have to set the bearing adjuster just lighter than this before you torque the nut, as it adds some force to the bearings too). Then I'd ride it on a straight road, take almost all the pressure off the bars and see if it'd weave slowly. I'd repeat this whole process until I had the highest torque setting I could without the bike weaving in a straight line. Over torqued headbearing don't allow the bike to automatically straighten itself out well enough due to the friction creating a weave (that's what trail does, it makes the steering self center), but too loose and I found the bike would head slap on gnarly pavement.
>How did the ME33's handle at slow speeds? Did it track true or weave?
The ME33 is great at slow speed, never a weave, and its provides neutral steering. Now that the ME1 rear is squaring off though, the ME1 is creating a bit of a weave in a straight line if I get sloppy on the bars, and its starting to flop into turns. Its the rear tire though. With a new rear, and the front in any condition, it doesn't flop into turns. I mentioned the bike has a tendency to steer from its arse. It even understeers a bit coming out of corners when on the gas hard. Ya, it definitely stands up way too much on the brake, but this is a function of its antiquated steering geometry (too much trail I think).
* Head bearings were new tapered rollers
. The best torque setting was the tightest I could go without having the bike weave in a straight line. This provided steady handling without too much "steering damper" effect. Even 5 degree changes in torque seemed to make a difference. Too loose, and I could get too many head weaves exiting bumpy corners hard on the gas, too tight and it weaved. BTW, torque the top nut above the triple clamp to spec and no tighter or it'll be impossible to properly adjust the bearing.
* Swing arm bearings:
It was a tank slapping beast with the old bearings and would also have too much rebound damping (the rear would lose traction over rippled pavement as it packed down). I installed new swingarm bearings/bushings/seals just before the trip and it greatly increased composure of the chassis, and I never had the rear pack down. Kawi recommends lubing these every 6000 miles, but they should be done at least once a season (mine looked like hell when they were removed).
The Avon Super Venom rear I removed had crappy traction. The new Metzeler Me1 Comp K made the bike seem like a different machine. After Highway 17 up the mountain in west Vermont (great road), the edge of the tire was shredding a bit but gave great grip and neutral steering. The draw back is that it started to square off after 1500 kms, and I doubt I'll get more than 4000 kms out of it (2500 miles or so). It was worth it for this trip though. The ME33 comp K front was predictable and fine steering as always. The bike stands up a lot on the brakes so you can't trail brake the front into corners without paying the price of a slower exit drive, but I don't know how much of this is due to tires (I doubt it, its probably the acres of trail in the chassis design).
* Rear eccentric chain adjuster:
As I wrote in the GPz mod FAQ, flip this upside down to get more rear ride height (about 1"). With it flipped, it gave just enough clearance to go off the edge of a 140/70 rear while touching the pegs, and the bike steered quicker and neutrally.
* Fox shock:
I found the best settings were 3 to 4 on compression damping and 6 out from max on rebound, with 1.25" sag. I'd like to have set less sag on the rear (harder) as I found it squat steered from the arse a bit much, but didn't have time. The compression keeps the bike steady, and is just under my pain threshold on expansion joints. The heavy rebound damping helps the flimsy frame settle after nasty mid corner bumps.
* Fork oil weight:
I ran 15W with Progressive springs (1" sag) and a fork brace and it kept the bike composed. The Kankamangus is a very bumpy highway, and the fork never felt too hard for good handling. Front end feel was pretty good, and the front rarely budged in bumpy corners. I may try 10W to get better front end weight transfer, but changing weight effects rebound more than compression and I don't want any less rebound so I probably won't.
Man this thing needs bracing! With the harder suspension set up, the frame was left to absorb the bumps. I tell my friends on new Hondas that the GPz had the original tuned chassis concept. Never bad enough to cause a long weave, but I did have a few manageable headshakes on the Kank getting on the gas out of bumpy corners. One really important point I forgot to mention about chassis set up: The Kawi eccentric chain adjuster scheme has a tendency to not line up the rim correctly. You set both sides to an equal number of lines on the adjuster, and the rim isn't quite pointed straight ahead. My friend has the exact same problem on his new ZX-11.
Using a ruler, I measure the distance from the edge of the rim to the swingarm, and make sure they are equal on both sides. On many Kawis, this involves having one eccentric adjuster set to a different point than the other. I find that making sure the rim is dead-nuts straight ahead significantly extends chain life, and makes the whole power train feel smoother. I never had to adjust my chain once on the trip, despite significant and fairly constant abuse.
I put on an aftermarket pipe and kept the center stand. As the stock pipe has the bumper that holds the chain, I had to make something that kept the stand out of the chain. I take a flat piece of steel, bend the end, and mount it in the old exhaust mounting hole on the right side rear passenger peg bracket. The piece is long enough so that the center stand just clears the chain, even with my new gearing that made the rear sprocket larger.
I order PBI sprockets from one of my sponsors that sells motorcycle accessories. I have no knowledge of a company ph #. Accept "NO OTHER" brand as PBI is the strongest and made correctly (same as factory) for the offset needed on the GPz. The model is # 495 and you tell them the pitch and tooth number that you want the sprocket to be. PBI sprockets are easily identifiable as they are stamped with either PBI and / or the sprocket # 495 X (X meaning that the sprocket is not factory 630 pitch) . I can't hook you up direct with PBI as they only sell to a few distributors and you have to be a dealer to order from these distributors. I know this because I called PBI and their major distributor.
Here is the place to call for your sprocket.
Street + Comp ph # 800 - 326 -5487 They are located in Troy, NY and I spoke with "Dan" and he said they accept all major credit cards and COD.
The PBI sprocket number is # 495 and you have to specify that it be 530 pitch and the number of teeth you want. The sprocket is special order as they don't offer a conversion sprocket set for the GPz model. He said the sprocket will be about $20 - $25 plus shipping. The rear sprocket can also be had from Sprocket Specialties in only aluminum in 2 to 3 weeks time. The gold plating that is applied to the sprocket actually makes the teeth surface tougher giving you longer wear. It's a $8 to $10 deal that might be worth that much extra sprocket life.............. Mark
FYI - I ordered PBI 530 sprockets from the speed shop in NY that Mark suggested - they said the cost would be $26 for the front, $58 for the rear plus shipping. They can get them to me in Montana in three weeks.
I also bought an aluminum 530 pitch 44 tooth SS rear sprocket that has been coated with a material to extend the sprocket life for a retail price of $59.95. This sprocket only weighs 1 lb. 9 oz ( .708 kg ) but aluminum sprockets don't have half the life of a steel sprockets and at double the price it's expensive. Both of these sprockets will run with a 18 tooth PBI counter shaft sprocket for clearance of the swing arm. I'm going to check the offerings from PBI on "rear" sprockets and see if they will custom cut steel to your requirements.
Many 80-85 Kaws (all models and cc's) had "rear" brake discs that were the same ID and OD as the front brake discs of the GPz750. These rear discs measured "over" 6mm thick. Buying these rear discs used and surface grinding them to 5.1mm is a great way to get brand new front rotors for the GPz750 at reduced price. The stock rear brake rotors are much too thick and one can easily run one as thin as 4.5mm on the rear wheel. My race bike has had rear brake rotors as thin as 4.5mm that didn't warp even though they were dark blue in color. NHRA dragracing rules states that the brake discs we use must be a minimum of 4.75mm in thickness.