YZ426 no power in the top..

I have a 2001 yz426 and just installed a Wiseco 13,5:1 piston and a DR.D complete exhaust.

The bike runs great, no shooting or anything and great buttom 2 stroke wannabe snap.. The only problem is that at higher rpms it has no power.. :cry:

My jetting is 162, 72, 42 with needle in 4. clip. I tried to raise the needle one clip, but that made it run like crap.. I race at sea level, 10deg cel.

Always clean filter.

What´s my problem???

Hello Jesper, I think you are on right track, obviously it cannot get enough fuel. Try a larger main jet and open the fuel screw a quarter turn. Besides being at sea level it is quite cold already there also, we have today -8 C. You are rich on oxygen.

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