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Main Area => General GS500 Discussion => Topic started by: dcoffey48 on June 14, 2011, 02:24:32 PM

Title: Carb tuning question:
Post by: dcoffey48 on June 14, 2011, 02:24:32 PM
I just re-jetted my 89 GS500e.

125 mains
40 pilots
2 washers

It runs fine with one exception:
When coming off of the throttle, the rpms don't come down right away.  They stay high for quite a while.

I started with 3 turns out on the idle mixture screw.

Any suggestions?
Title: Re: Carb tuning question:
Post by: Big Rich on June 14, 2011, 04:57:53 PM
Choke isn't shutting all the way or an air leak around the intake. Most likely an air leak.
Title: Re: Carb tuning question:
Post by: ben2go on June 14, 2011, 06:41:02 PM
Sounds like a vacuum leak to me also.
Title: Re: Carb tuning question:
Post by: centuryghost on June 14, 2011, 08:34:30 PM
I'll x3 that only if you give some more info; like what air filter and exhaust you have going on...
Title: Re: Carb tuning question:
Post by: dcoffey48 on June 15, 2011, 05:42:52 AM
Quote from: centuryghost on June 14, 2011, 08:34:30 PM
I'll x3 that only if you give some more info; like what air filter and exhaust you have going on...

Stock exhaust and Stock air filter.

I did a visual check on the carb connections and it looks fine, good and tight.  Is there a better way to check this? Maybe spray some starting fluid in that area while it is running and see if the engine speed changes? The choke is disengaging as well.  The only Vacuum line/connection as I recall was the one that goes to the petcock diaphragm/valve.  Is there another one I missed?

Dave.
Title: Re: Carb tuning question:
Post by: Big Rich on June 15, 2011, 05:47:01 AM
Anything but starting fluid. Ether is extremely flammable. Try WD-40
Title: Re: Carb tuning question:
Post by: scratch on June 15, 2011, 12:59:37 PM
Make sure the tiny o-rings under the diaphragm covers are still there.
Title: Re: Carb tuning question:
Post by: dcoffey48 on June 15, 2011, 05:24:00 PM
you guys called it.

I sprayed some starting fluid very lightly and directly on the intake manifolds left and right individually.  The left had no effect but the right cause a drastic increase in rpms.

I guess I'll have to look into further. Maybe new rubber intake boots.

Thanks,
Dave.
Title: Re: Carb tuning question:
Post by: crzydood17 on June 15, 2011, 09:45:10 PM
i just pulled mine apart today, check the seal between the head and the boot mine was leaking ever so slightly, i could see dried gas varnish on the mating surfaces. I cleaned the surface put a tiny bit of oil on the gasket and popped it back on good as new fixed my hanging idle for now at least.