Bonneville America Forums Forums Technical Forums Performance Mods carb mixture screws: how many turns out is ok?

hello all,

awhile back my motorcycle mechanic told me i needed some head work because of compression issues. i was slightly popping on decel. i managed to almost get rid of it by turning my screws out more but now they're at 4 turns out. it's been awhile since i messed with them and the last time i did i think there was some issue on if i went up a jet size it would be too much. sorry but i don't what jets i'm running in there now. my question is, for a quick fix, how many turns out is ok before it's too much? thanks fellas.

If you need 4 turns then your pilot is too small, I consider 3 turns out to be max before going up a size. You should adjust by turning the screw in until the bike runs rough then back out until it runs rough the correct setting is 1/2 way between those 2 points. I find it easiest to disconnect 1 plug wire and turn the idle up just enough to run on the cyl. still connected. Ground the disconnected plug wire before starting. With the bike idling on only 1 cyl. it is easier to hear when the cyl. starts to run rough. Some popping is normal, if you eliminate it all together you are probably running rich, the less restricted the pipes the more popping you will have. That being said it shouldn't backfire but rather a sort of rumble.

thanks. i'll check to see what pilots i'm running. it was definitely back firing. i went another 1/8 and it seemed to help a lot but i guess they're too far out now.