I have a 01 mxz 800 all up dates done. I am putting a rktek head on it. What should jetting be? 430 main? what neddels or should i just shim stock? If so what shims?

I ride in Michigan and have the 01 800 twin with the RKT head. I have been running 420 mains with the 942 needles, clip in second groove from the top. EGT's have been good so far, 0 degrees and above. If you are running a very tight squish and/or high compression with this motor be careful about your gas you buy. I had a ring go bad last week and I think it was because of detonation.

Thanks where can it get the 942 needles