gs550t need help!!

[cafe1253]

I have a 1981 gs500t when i turn the headlight on the idle drops. I also cant figure out, when the bike warms up the idle gets worse. By worse I mean it goes up and down it wont hold steady. The odd part is when the bike cools down it idles fine again untill it warms up. I am not sure if its an electrical thing or not.
could it be a stator?

Any help would be great thanks everyone

[koolaid_kid]

Have you checked the voltage at the coils before and after turning the headlight on? Sounds like a voltage drop to me, which some version of the coil relay mod should fix.

[old_skool]

I have a 1981 gs500t when i turn the headlight on the idle drops. I also cant figure out, when the bike warms up the idle gets worse. By worse I mean it goes up and down it wont hold steady. The odd part is when the bike cools down it idles fine again until it warms up. I am not sure if its an electrical thing or not.
could it be a stator?

Any help would be great thanks everyone

The idle variance after warm, may be due to a vacuum leak, the o-rings on the intake may be leaking after it warms.

[koolaid_kid]

The idle variance after warm, may be due to a vacuum leak, the o-rings on the intake may be leaking after it warms.

Actually when there is a vacuum leak the idle usually increases dramatically when the engine is warm. I test rode an 850 that started out at normal idle, when I returned from the test ride it was idling around 3500 rpm.
The idle variance could be a symptom of low coil voltage, at least it was on my GS. A relay mod brought everything back together.
At any rate, a voltage check will do no harm and may pinpoint the issue(s). (There could be multiple issues, where one is covering up others.)

[old_skool]

Actually when there is a vacuum leak the idle usually increases dramatically when the engine is warm. I test rode an 850 that started out at normal idle, when I returned from the test ride it was idling around 3500 rpm.
The idle variance could be a symptom of low coil voltage, at least it was on my GS. A relay mod brought everything back together.
At any rate, a voltage check will do no harm and may pinpoint the issue(s). (There could be multiple issues, where one is covering up others.)

Yeah, now that you mention it, thats how the 650 acted till I replaced the o-rings, may vary well just be a voltage issue, or a combo of things depending on how far he's gotten with the maintenance.

[cafe1253]

First off thank you for the quick replies
As maintence goes the valves have been adjusted, carbs synced, previous owner states boots and rings are new(Iam not sure), Also I hear alot about the coil relay mod what is it and how do I do it. Honestly electrical work is not my strong suit. Any help is greatly appreciated
Thanks

[cafe1253]

could the magneto igniter be going bad when the bike gets hot??

[old_skool]

First off thank you for the quick replies
As maintence goes the valves have been adjusted, carbs synced, previous owner states boots and rings are new(Iam not sure), Also I hear alot about the coil relay mod what is it and how do I do it. Honestly electrical work is not my strong suit. Any help is greatly appreciated
Thanks

Who rebuilt the carbs, just how detailed in the rebuild did..who go, who synced the carbs, you cannot rely on others maintenance, the stator should not have anything to do with the idle isue, it sounds like a 2 fold issue, starting with the carbs still and ending with a possible charging problem, you need to go through everything and eliminate it by testing, don't just throw parts at it hoping to find a cure, read up on the stator papers, test your stator and RR, make sure all your connections are good, test battery, and you may have to properly disassemble the carbs and dip them properly and replace with new o-rings, read up on bikecliffs site and go through all the maintenance items first.

[koolaid_kid]

First off thank you for the quick replies
As maintence goes the valves have been adjusted, carbs synced, previous owner states boots and rings are new(Iam not sure), Also I hear alot about the coil relay mod what is it and how do I do it. Honestly electrical work is not my strong suit. Any help is greatly appreciated
Thanks

This is a good example of the relay mod: Coil Relay Mod

[cafe1253]

I actually did all of the carb and sync. The carbs were properly taken apart and dipped. Could a rich condition mess with the idle?