This dyno chart shows the effects of the K&N replacement air filter for the stock R1 airbox. Dyno run 30(blue) is a base run with the stock air filter. Dyno run 33(red) is with the K&N air filter and no change in jetting. As expected, the additional airflow from the K&N without an increase in main jets size caused a hp loss. Dyno run 36(green) is with the K&N airfilter and raising the main jets 1 size. At this point, we are back to where we started with basically identical hp to the stock airfilter and jetting. We're on the right track but still don't have quite enough fuel to compensate for the additional airflow.


Dyno run 54(blue) in this chart is with K&N air filter and up 1 size on the main jets. Dyno run 58(red) is with the K&N air filter and up 2 sizes on the main jets. While there are no peak hp gains, there are small gains in the mid-range and some very nice mid-range torque gains. What you don't see on this graph is the all-gears dyno run. In the all gears run, the hp on the 1 main jet size increase run dropped off across the board in each gear. This is an indication of the fuel mixture being too lean. In the all-gears run for up 2 main jet sizes I pickup up a solid 2.1 hp in the top 3 gears.


These 2 dyno charts show a comparison between the K&N filter plus up 2 main jet sizes(runs 64 & 66) vs. up 3 main jet sizes(runs 68 & 70). These runs were done on a different day from the previous runs. As you can see, there is not much difference other than a small peak hp loss on the runs that were up 3 main jets sizes. Therefore, I went back to up 2 main jet sizes with the K&N.


CONCLUSION: This was a learning experience. Other R1 owners and tuners had installed K&N filters and had reported hp losses on the dyno. I took it as a challenge to see if I could get some gains on my own. While I did not pick up any peak hp, I did pick up some mid-range hp and torque which will help my bike accelerate quicker. Isn't that what we're really after??? The K&N filter also helped boost my peak torque up to 80.0 ft/lbs. of torque.

Was the K&N filter worth the time and hassle? No, probably not. But now that I've figured out the jetting, maybe other R1 owners can just install the K&N, go up 2 main jet sizes, and not go through all the dyno time hassle that I went through. If I had seen this test before hand, and knew what the proper jetting was without having to spend hours on the dyno, then yes.....I probably would have gone ahead and purchased the K&N filter and bumped up my main jets. I hope this has helped some people.