Bonneville America Forums Forums Technical Forums Performance Mods stuttering at 3/4 to full throttle.

2 shims on Thruxton needles ?!!! That may well be the problem. The needles WILL cause cutting if too rich even at WOT let alone 3/4 throttle. How do i know? Cuz i tried that too. One shim on thruxton needles caused mine not only to stutter, but at wot the engine stuttered and died well before the limiter usually kicks in. Thruxton needles are very rich, and i couldn't run them with any shims at all. Why you are still getting popping musthave to do with the pilots i'd think. Maybe thier size RELITIVE to the neddle setup has something to do with it.