Bonneville America Forums Forums Technical Forums Performance Mods Idle speed ?

I'm sure this has been discussed many times before but hey let's talk about it again
Idle speed fluctuation. What causes this, and what is the cure?
I'v seen this discussed in brief on other ocassions. Apperantly it is something a lot of us are experiencing.
Mike

I can only comment on the cure in my case: I linked the vacume ports of both carbs. THIS fixed it. NO MORE idling problems!

Hi Ya, Dannyboy. I'v been running that for several thousand miles. I have never noticed a difference with or without.
thanks for the suggestion.
Who's next.
Mike

Small variations over long periods of time are the result of changes in temperature and atmospheric conditions. Wide variations over very short time periods (Sits there going grunk grunk grunk like a badly tuned diesel) is usually caused by a vacuum leak.

My experience, especially with older bikes, is that idle decreases as your valves recede (tighten up). Once valves have been adjusted, your idle usually goes back to normal. BUT.... after a valve adjustment, it's recommended to re-check your carbs (for sync & idle).

bump

Since you bumped it I assume you didn't get the answer you wanted. The only way I ever successfully got rid of ALL the idle fluctuations was to swap out to the Mikuni carbs. It idled absolutely perfect with them. But with the stock carbs the best method seems to be sure they are sync'd properly and have the crossover hose connecting the two.
Mine has slight variations, but only after a lot of riding, it doesn't flucuate sitting still, it's either right around 1100 rpm or up to about 1200 after it gets really warm. It is inherent in the design in the CVK carbs I attribute it to. As well as the temperature/humidity etc, they all contribute to it.
So, if you really dislike it, or it bothers you that much, Give Bill Gately a shout, for about $1500 you can totally eliminate it. I also hear that the $500 CV carbs correct it as well.

Hello Pat. Thanks for the reply, I guess. What beer you drinking these,Mad Cow? Or is it bitter beer face. Your last few replies seem to have a " I wish these people would stop asking questions" response.
Brother I'm just trying to make my scoot run the best and smoothest as possible without spend $ 1500.00 and several months on something that sounded good in the beginning but just did not work out. No whatta mean!
The carbs are sycn'd and the crossver tube is in place as has been the case for many,many moons.
I started this thread because my bike and apperantly several others are experiencing the same issue.
If it's something we have to live with then so be it. Just thought some of you shade tree guys might have a fix.
Peace out

Pat,

I am having probelms with idle speed, but it goes beyond just fluctuation. I just installed a set of the SS Short Slash Cuts and I am having problems with the bike stalling out while at idle. AI out, snorkel out, Uni Air Filter in. 135 mains, 45 pilots and 1 shim under the needle, 3 1/2 turns out. Noticed that the plugs seem black everywhere but the electrode. Got any ideas? Tried 3 turns out also but with more popping on decel. Maybe I don't need the larger sized pilots or shims under the needle.

I would put the stock pilots back in and try that.
Black plugs are a sign you are way too rich.
Try a new set of properly gapped plugs too.

mikemm03,
Sorry if it sounded like a smarta$$ answer, wasn't intended to be.
But it is something that most of us experience with the stock carbs. I think that maybe drilling out the little magic hole to 7/64" may also help. This stabilizes the vacuum a bit more. Maybe I'll do that next time I yank mine off.

Thanks. I will put the old pilots in and give it a try. I am also thinking about giving a set of the Iridium plugs a try. Anyone here tried the Colortune Spark Plugs for setting up the air/fule ratio? I have heard pros and cons (the con mainly being bad threads on the Colortune Plug).