Bonneville America Forums Forums Technical Forums Performance Mods Carb questions...

Newbie to all this, especialy carbs... Anyway I have an 07 speedy, AI removed, Freaked, Short pipes(see straight through them)Gutted screaming eagles actually. I have a whicked flat spot around mid throttle, or mid range and some popping on decel, not real bad but I think too much.
Havent touched the carbs exept change mains with what Brent sent me with the freak, which were 160's (Seems too much) Havent seen anyone here that high on mains. Throttle response doesnt seem to be the best either. Checked the carb site, still not sure cause of the wide open pipes and big mains. Any help would be appreciated
Thanks

After a lot of wrestling I finally discovered that I was running lean, and that I did, in fact, need the 160 mains -- so that's a good call. In fact I may even need to go up to 162s, but I have some more experimenting to do.

How many miles? Need a valve adjustment? The book says 12k miles, but given how out of whack mine were, I'd say do it at 10. Also, you should prob bump up the pilot jet and put a couple of shims on the carb needles.

I'm no genius at this, I promise -- I'm pretty stupid, honestly -- I'm just regurgitating common wisdom around here. Sounds like you're on the right track, tho!

--Jaeger

Cool, thanks for the input, ( I thought i was way to high on the jets) shes only got 2400 k on her so valves should be good, Where do you get the shims? and what about drilling the slides ...I saw this on Pats web site there, do those holes go all the way through or what,
Thanks Again

correction 2400 Miles

150 to 160 mains should be right. I'm thinking your flatspot starts going away at around 3000 - 3500 RPM. That is about where the slides start opening and the carb starts switching over to the main jets. Until the slides open, you are running mostly on the idle jet and a couple of transition ports fed by the pilot jets. Because of this, You will probably get it sorted with bigger pilots and maybe Thunderbird Sport needles.

Yes, what Greybeard said.......also your '07 won't need the slides drilled. They already are.

160 in many cases is too big and if you haven't replaced the pilot you need to. If you dyno I bet you will find you are scary lean until mid throttle. Might try the TBS needles for the mid range flat spot.

TBS needles and 45 pilots, got it
Thanks guys

even try a few shims, cheap and easy and go from there

Frank

I agree with Frank. Try shimming the stock needles first. Start with one shim. The easiest and cheapest troubleshooting you can do. Work up (TBS needles/45 pilots) from there.

Just ordered 45 pilots, and shims, the shims brings the needle up higher so the tapered bottom part of the needle lets more gas in, The TBS needles are thinner, more tapered, is that right. So basicly the same result only cheaper?