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.. 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???