I am running an '86 bored .100 over, cool head and 21cc dome, fmf fatty and Q silencer, 38mm PJ and I've tried jets from 170-190 and the plug never seems to look like it is running rich, it will run fine 1st-3rd and bog out at WOT shifting through the gears. The motor was rebuilt less than 12 hrs ago with a hot rod crank, new OEM counter balancer and Wiseco piston. I run a twin air filter with no air box lid. My four wheeler seems to run okay occasionally for 10-15 minutes and then just cut out at WOT. Any ideas?