GS 450 New Problems :( :(

[MikeQ]

Hi Guys.

I have a 1980 GS 450 L. After cleaning my carbs, the bike seemed to be sticking at 3k. It would idle, but as soon as I revved to 3k or higher, it wont go below 3k for 5-60 seconds. Pete suggested old boots, so now all the intake boots, carb/airbox boots, and orings are new.

At this point, If the idle stop screw is fully backed out, disabled so to speak, the bike rides perfect. I had it riding today. smooth, ect. The minute I turn the idle stop screw so the bike is idling, it hangs at the 3k. Is there some fluke with throttle cables or something funky? This makes absolutely no sense to me..

When I say I rode the bike today, I had to keep it running via the throttle alone. This is very difficult..

Can't exactly ride it safely the way it is right now...heh

Thanks guys

[Tamara]

When I was having idle issues with my 450, one of the suggestions I was given was check the valve clearances and adjust as necessary.

[koolaid_kid]

It sounds like you are too lean. You can either use the fast idle method on BassCliff's web site to set your idle mixture screws, or the procedure in my signature. Success has been reported with both methods, YMMV.

[MikeQ]

Would a lean condition explain the bike not hanging with the idle screw disabled, but hanging with it at normal idle?

[koolaid_kid]

It might. How did you set your idle mixture screws when you re-installed the carbs?

[nejeff]

It sounds like you are too lean. You can either use the fast idle method on BassCliff's web site to set your idle mixture screws, or the procedure in my signature. Success has been reported with both methods, YMMV.

Koolaid with your method or the fast idle method is it understood to have the carb sync done before the idle adjustment or after, or does it matter. I have always wondered this and did not know the accepted order

[koolaid_kid]

IIRC I synched the carbs using a Morgan Carbtune first, did the idle adjustment next, then verified the synch after. It needed no adjustment at that time.
The thing to consider about the carb synch is that you do not need to rev the engine up while performing the synch. To set the mixture screws you do need to rev the engine up and see if it performs correctly.

[nejeff]

IIRC I synched the carbs using a Morgan Carbtune first, did the idle adjustment next, then verified the synch after. It needed no adjustment at that time.
The thing to consider about the carb synch is that you do not need to rev the engine up while performing the synch. To set the mixture screws you do need to rev the engine up and see if it performs correctly.

Ok, getting ready to fine tune the 550 and wanted to verify, thanks very much

[jeffasaurus2]

I know that after I rebuilt the carbs on my 450T they had a hanging idle with nearly the same symptoms. I was able to fix the issue with a carb synch, and then tune the mixture screws properly afterwards.

[pete]

Bugger! I thought new boots would definitely sort that if it was a vacuum leak... hopefully a balance and adjustment will fix it properly...

[koolaid_kid]

A number of years ago I rode a bike with a vacuum leak. It was a 79 GS850 that a GSR member was considering purchasing. The purchaser asked me to test ride it for him, which I did. When it first started up, it was O.K., but as I rode it around the idle rose until it was idling around 3-4k. And it would not go down, no matter what I tried. Turned out to be the carb boot o-rings. My only personal experience with leaks.