It seems that Yamaha has developed a number of different YZF-R1 CDI units (or black boxes) for different markets around the world. Much speculation has been put forth as to the HP differences between each box. There appears to be a strong case for the theory that the European black box (part number 4XV-82305-00) makes more HP than the others. Judging from dyno tests throughout the world, the European YZF-R1 seems to make greater horsepower differences over the ZX-9R and 900RR(Fireblade) in the European tests. At this point in time I know of 7 different black boxes used by Yamaha on the YZF-R1. They are as follows:

4XV-82305-00 England and most of Europe
4XV-82305-05 England (restricted?)
4XV-82305-10 Sweden, Belgium (restricted)
4XV-82305-20 France (restricted)
4XV-82305-30 USA 49 States
4XV-82305-40 USA California
4XV-82305-50 Australia

With cooperation between members of the YZF-R1 mailing list and YZF-R1 Forum, we are trying to quantify just what these differences are in terms of horsepower. A French race team recently dyno tested a R1 and found the 4XV-82305-00 box to make 8 horsepower more than the French 4XV-82305-20 box. These differences would be expected to some degree because France is a "restricted" horsepower output country. The test that I am most concerned with would be between the European 4XV-82305-00 box and the US box 4XV-82305-30. Currently, I know someone in the US who has ordered the 4XV-82305-00 box from England and who hopefully will be conducting a dyno test sometime in the near future.

The results are in! A great big thank you goes out to Jeff Jerome for conducting the "30" vs "00" black box dyno tests. Let me just quote what Jeff wrote about his dyno tests:

"After 50+ runs with the 00-box against the 30-box I can honestly say there is no difference in peak horsepower between the two boxes. The only difference on the dyno was a small increase (1-2 hp) in the hp/torque between 5800 and 8000 rpms."

"I did watch the EXUP valve with both boxes and the 00-box still has the retard (open) position in the first three gears just like the 30-box. Final conclusion is that if you have the 30-box, I would not purchase the 00-box!"

It looks like the great black box mystery is over. These results are similar to the kinds of results the EXUP Brotherhood was getting by modifying US FZR1000 black boxes to match the configuration of the Canadian boxes. As I remember, they saw from 2-4 ft/lbs of torque in the mid-range from these modifications but 0 additional peak hp.

Now the question becomes: Is there really any real hp output differences between the US and European R1's? From reading the initial YZF-R1 reviews in Superbike, Fast Bikes and Performance Bikes it sure appeared like the English bikes had a 5-7 hp advantage over the US bikes.

I'm beginning to wonder if this was just pre-release hype by the English magazines or if Yamaha sent a few "optimized" bikes to England for initial magazine testing. I am continuing to try to find out if there is any differences at all between the US R1's and the English R1's. At the moment I am trying to obtain part numbers for the camshafts, carburetors and pistons. I have already found out that both the intake and exhaust cams are identical between countries.

I now think that US YZF-R1's are essentially identical to their European counterparts. US magazines are getting from 129-131 hp at the rear wheel. English magazines are getting up to 142 hp. There could be several explanations for this differnce. Some English magazines use a Fuch's dyno which reads hp off the front sprocket, not the rear wheel. This will give inflated hp numbers. Also, some European Dynojet dyno facilities use DIN hp ratings instead of the SAE standard that is used in the US. The only difference in the two is that DIN does not take humidity into account when determining the correction factor used. This could lead to higher hp readings also.

I've finally found one difference, English and most European R1's have factory installed adjustable carb needles. The US bikes have non-adjustable carb needles. I need to get my hands on a set of these English needles. At this time, I have no idea what effect on hp these adjustable needles have.