we put a fhm pipe on my son quad it seem to run great except the plug was running a little white at 3/4 to wige open ,Fom idle to 1/2 the plug
is a little black.instaled a 150 main jet raised the needle 1 notch,quad still running great plug is almost a nice nice tan color at the 3/4 to wide open,goint to try the next size up,but now at idle at to 1/2 the plug is white to lean,tryed to adj the mxture screw and the plug stayed the same so I am thinking that the pilot jet is to small and need to go bigger?

sound right to ya