popping at 1/4 throttle

[racer36]

my quads popping at about 1/8 to 1/4 throttle. ive been all the way from too rich to too lean on the jetting with no success at finding the sweet spot. it has fmf powerbomb and silencer, athena 460 kit, hot cams with cam mod. also all valves are in check.

any suggestions on what to try?
any help is great!
thanks