Author Topic: Air leak in throttle linkage  (Read 859 times)

Offline Soloratov

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Air leak in throttle linkage
« on: April 18, 2012, 07:12:52 PM »
I have been able to seal up everything nice and tight but I noticed a slight air leak in the throttle linkage. I believe thats the right term. THe round bar that runs through the carb bodies. Anyway, I sprayed around them and it seems the only leak is on the end that has the e-clip. Right side. My question is, can I fix this in place? I noticed there is some type of foam ring under a plastic washer, which is under the e-clip. Could I maybe just replace this with an o-ring or rubber seal of some kind, or do I need to take these babies apart again? Trying to avoid just because I am not too sure I will be able to remove the butterfly plates that are attached to the linkage bar without destroying the screws.

Offline ATLRIDER

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Re: Air leak in throttle linkage
« Reply #1 on: April 18, 2012, 07:24:26 PM »
Not certain but it sounds like your choke circuit.  If it is then you don'thave to remove the butterfly. The choke mechanism is replaceable.
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Offline Soloratov

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Re: Air leak in throttle linkage
« Reply #2 on: April 18, 2012, 08:03:27 PM »
Stole this pic from the sticky:



The "Throttle Shaft". I sprayed right onto the e-clip and noticed an immediate drop in rpm.

Offline BaltimoreGS

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Re: Air leak in throttle linkage
« Reply #3 on: April 18, 2012, 08:32:42 PM »
I know craigs449 was having the same problem, not sure if he ever fixed it.  A temporary solution is to stick a vacuum cap over the whole thing.

-Jessie

Offline craigs449

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Re: Air leak in throttle linkage
« Reply #4 on: April 18, 2012, 08:54:27 PM »
Baltimore is right...I have the same issue with my carb(s)........and I am sure that is the cause of the hanging idle when she is warmed up.  I picked up some vacuum caps from the local auto parts store and put one on the left side of the left carb but the other areas must be leaking too.  A look at the parts fiche shows no replacable parts in that area, it's just part of the carb body.  As far as I can tell, you don't want to seal that are up with anything that might keep the butterfly's from opening and closing so the vacuum caps are the best solution I can think of.  I need to find time to pull the tank and cap off the other three areas too to see if that solves my hanging (3000-4000 rpm) idle when she is warmed up.
2001 Suzuki GS 500 "Commute Killer"
2008 Husqvarna 510 SMR
2002 Honda CR 250 "Project Pain-in-the-ass"
2001 Honda XR 50

Offline Soloratov

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Re: Air leak in throttle linkage
« Reply #5 on: April 18, 2012, 10:00:53 PM »
The vacuum cap idea is quite novel. I will gove that a try tomorrow. Thanks!

Offline craigs449

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Re: Air leak in throttle linkage
« Reply #6 on: April 25, 2012, 09:07:29 PM »
TTT.... :dunno_black:  Capped both side with greased vacuum caps and the hanging 4,000 rpm idle persists.

When I got to work today, I remembered some stuff from here and tried something.........with the bike running, I pulled the left plug coil and she died instantly.......put it back on, fired her up, and pulled the right plug coiul and she idled like sheet, but she idled.  So I assume the source of my idle problems are out of sync carbs..............It's possible that the PO might have fooled with the sync screw when he made an attempt to clean the carbs after the bike sat for a year.....

Good thing BaltimoreGS just posted a vid that I can watch for sync'ing the carbs.. :cheers:
2001 Suzuki GS 500 "Commute Killer"
2008 Husqvarna 510 SMR
2002 Honda CR 250 "Project Pain-in-the-ass"
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Offline adidasguy

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Re: Air leak in throttle linkage
« Reply #7 on: April 25, 2012, 09:11:25 PM »
Time to try my Hillbilly Carb Sync method!

Offline craigs449

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Re: Air leak in throttle linkage
« Reply #8 on: April 25, 2012, 09:16:05 PM »
Time to try my Hillbilly Carb Sync method!

Yeah buddy... :cheers:...Sending you a pm as I type......
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Offline BaltimoreGS

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Re: Air leak in throttle linkage
« Reply #9 on: April 25, 2012, 09:21:06 PM »
Time to try my Hillbilly Carb Sync method!

Yeah buddy... :cheers:...Sending you a pm as I type......

If you feel like riding up to Bmore you can use my manometer.

-Jessie

Offline craigs449

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Re: Air leak in throttle linkage
« Reply #10 on: April 25, 2012, 09:26:17 PM »
Time to try my Hillbilly Carb Sync method!

Yeah buddy... :cheers:...Sending you a pm as I type......

If you feel like riding up to Bmore you can use my manometer.

-Jessie

Thanks, gonna give the hillbilly method a shot first to see if I can get her closer to sync'ed than how she is now which is garbage.
2001 Suzuki GS 500 "Commute Killer"
2008 Husqvarna 510 SMR
2002 Honda CR 250 "Project Pain-in-the-ass"
2001 Honda XR 50

Offline cheetahman

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Re: Air leak in throttle linkage
« Reply #11 on: April 26, 2012, 10:14:54 AM »
I had a similar problem with a different bike not a GS obviously, back in the mid 80's.  I was blasting around Daytona during bike week and my bike was just running horrible as if it were very lean, (because it was) yet I could not find the air leak even after spraying all the known joints, such as carb to manifold gasket, and manifold to head joints, with WD40, no dice.  I even changed the seals from the manifold to the heads which is not a fun job in a campground, and still no luck. 

I happened on the worn throttle shaft mostly by accident as I stared down the throat of the barely idling carburetor and revving the throttle watching as the butterfly moved and the gas sprayed in.  Suddenly I noticed the throttle shaft and the butterfly literally dancing around, as I let off the throttle and the engine returned to idle.  This was a highly modded motor and the pulses in the intake track were violent to say the least.  I had no parts available to fix this carburetor so my fix was to put a glob of the stickiest molly grease I could find, over the end of the throttle shaft.  I carried the little tube of grease with me all over Daytona for a week and refreshed the gob every 50 miles or so. 

The fix back at home was involved because not only was the brass throttle shaft worn, but the hole in the carb body was actually egg shaped as well.  I bought a new throttle shaft and an oil-lite bushing to fit the shaft from McMaster Carr.  Then I had to drill out the carb body and press in the bushing.  A little bit of trimming and fitting the bushing and shaft, and finally the air leak was gone.  You can get a new throttle shaft for your carbs and hopefully that might fix it, but check the hole in the carb body.  because you'll only want a couple thousands of an inch of clearance between the shaft size and the hole size or you are right back in trouble with the air leak.  The problem with the vacume cap fix is that I don't think you can get one on the spring side of the carb.  Good Luck
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Offline Soloratov

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Re: Air leak in throttle linkage
« Reply #12 on: April 26, 2012, 06:31:13 PM »
I was able to cap off both outer areas with the cap and a hose clamp. Immediate difference! You are right, I can't really do anything about the spring side. It is so small of a leak if at all on that side I'm not too worried about it. I may fiddle a bit but it runs very well now. Slight popping on decel from 6k-ish but it's only 1 or 2 pops, and not all that loud. I am going to watch the plugs for the next hundred miles or so and see how they look.

Offline The Buddha

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Re: Air leak in throttle linkage
« Reply #13 on: April 26, 2012, 07:37:52 PM »
That is a rare and hard to fix location for a leak. But yea capping that whole thing is a good solution.
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