My 426 used to ride like a champ, but due to my insaciable quest for performance that i dont even use, i installed a Wiseco high compression forged piston, a set of HotCams and an YZ426 cdi. I timed the cams as i had them before, YZ timing, and now i have a serious problem to solve (or maybe not). I havent tested the bike in the woods yet, i only took an half an hour spin on the road because the guys at HotCams said that i needed to break-in the cams at midlle rpm`s and not to let the engine idle. So i did. The bottom and midle range is stronger without a doubt, even a woman could notice the changes, probably due to the raise of the compression ratio from 12.5/1 to 13.5/1. You can even notice the extra strenght you need to do on the kick starter. Back to my problem...when i am riding with 1/4 throtlle opened the engine is not smooth, in other words, the engine goes .....pof.......pof..pof.......pof.......pof..pof.....pof..... This type of failure only disapears at 1/2 to full throtlle. I have to consider the spark plug wear too. I never changed it before. Its still the factory one. Can some of you give some ideas on how to make that "failure" go away??? Is there any good jeting mod for my case??? Thanks.