Lingering Idle

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rcflier500

New Member
Nov 15, 2009
50
0
0
Upland, Ca
Hey all,
Ive returned once again for your help and expertise. The bike is running great except for one issue. When i pull the clutch in after riding some it revs up really high and then slowly comes down to idle. This will happen even if i just go to rev it at a stop. It seems like my mixture is too rich, but i am already at the leanest setting on the needle. I tried setting it one and two notches richer and it doesn't change the problem. Any help to remedy would be greatly appreciated.


Thank you!
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
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Maine
Usually when that happens it's a sign of a vacuum leak, check all yer gaskets for seepage - but odds are it's prolly yer intake manifold, either where the carby slides onto it and/or the gasket between the manifold and the cylinder. It's pretty common & easy to fix ;)

edit: seepage isn't always present, while some will spray carb cleaner or w/e around to find a leak (will alter idle when the leak is sprayed) I'd prefer misted water as carb cleaner can do a number on painted surfaces lol
 
Last edited:

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
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living the dream in southern california
it can also be a sticking throttle cable or slide. if the cap on your carb is too tight it could cause the carb to warp a bit, and the slide will stick, and cables just get sticky over time, especially if you don't grease them.

my bike started doing it a little a few days after it rained, and i found that the throttle cable was just taking it's time settling down.
 

rcflier500

New Member
Nov 15, 2009
50
0
0
Upland, Ca
it was both my intake at the cylinder and the carb. I was able to fix the carb leak, now i just need to make a new gasket for the cylinder.
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
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Phoenix,AZ
...if the cap on your carb is too tight it could cause the carb to warp a bit, and the slide will stick...
WOW Cool tip, I never thought of that! I have the same problem with a new build and the slide sticking!
I'll give it a try tomorrow.
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
It didn't fix mine.
I think it must be a flaw in the actual carb barrel.
I changed the slide too, no help. I just put a different carb on and all is good.

When I have a chance I'll see what I can learn about carb rebuilds and get some pics since I have 2 here that need it now.
Nothing beats picture examples in my book, and you don't have to type as much to explain ;-}