The 200 has a Keihen PWK35 carb. The PWK35 air stryker was designed for motcross bikes and to provide quicker throttle response. My 220 was running great with the 33 carb, but lacked the topend speed. Not wanting to bore my 33 carb like the RB mod does, yet wanting the performance gain, my dealer got me the 35 air stryker for $150. The 35 carb came with a 4.5 slide and a D series needle, this setup was extremely rich on the 220 and ran terrible. I decided to use the #5 slide with the stock KAW needle , 1173 I think, straight out of the 33 carb, and insert these into the 35 air stryker carb. After some jetting work, 158 main, 48 pilot, clip in the middle, this bike rips now. With 13/47 sprockets, there was no lose of bottom end but plenty gain on the top to be competitive. Its as quick as the 200's and only gives up a little topend to the 250's. I rode it in a 75 mile enduro this weekend and it did great. This was the mod that really made me happy with my 220.