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Main Area => General GS500 Discussion => Topic started by: Ry_Guy on May 02, 2008, 07:30:19 PM

Title: Right carb is lean
Post by: Ry_Guy on May 02, 2008, 07:30:19 PM
The right plug is ghost white. It must be running lean, because out on the road my GS runs like a champ.
It won't idle, so I can't balance the carbs.
I've adjusted air screws and idle screws and coated the intake boot with gasket goop, trying to eliminate an air leak.
I've had the carbs apart three times, they're squeaky clean.
Float height check turns out right.
Petcock is by-passed with a direct line from tank to carbs.
New plugs, fresh fuel.
I can't figure out where the air leak is coming from. What gives?
Title: Re: Right carb is lean
Post by: beRto on May 03, 2008, 07:38:55 AM
Quote from: Ry_Guy on May 02, 2008, 07:30:19 PM
The right plug is ghost white. It must be running lean, because out on the road my GS runs like a champ.
It won't idle, so I can't balance the carbs.
I've adjusted air screws and idle screws and coated the intake boot with gasket goop, trying to eliminate an air leak.
I've had the carbs apart three times, they're squeaky clean.
Float height check turns out right.
Petcock is by-passed with a direct line from tank to carbs.
New plugs, fresh fuel.
I can't figure out where the air leak is coming from. What gives?

Have you tried spraying WD-40 around to determine the source of air leak?

When was you last valve check? Carb balancing required that the valves are in spec.

You've said it runs well, but that it won't idle? I assume it idles too high? Does it have a hanging idle problem?
Title: Re: Right carb is lean
Post by: Ry_Guy on May 03, 2008, 09:27:15 AM
Valves were done a week ago. There was no reaction to the WD40 method.
Yeah, the rpms either hang high or drop to zero.
Title: Re: Right carb is lean
Post by: beRto on May 30, 2008, 08:25:01 AM
Any luck on this?

I forgot to mention that a common source of air leak is through the top of the carb; there should be a little o-ring in there that often gets lost (during carb rebuild etc). Without this o-ring, the carb will run lean.

This post gives some more info on the particular o-rings in question:
http://gstwins.com/gsboard/index.php?topic=41199.msg463434#msg463434