Electrical problems with 1982 GS300L

[Kentman7]

I have a 1982 GS300L. It has had electrical problems in the past. Those problems consisted of voltage spikes and drops that would increase/ decrease the bikes RPMs without the throttle engaged. I replaced the stator and the voltage regulator/rectifier and those electrical problems went away! The bike was riding great for 3 months!

now those electrical problems are back again. First the bike wasn’t idling properly, it would eventually die. Then I was having trouble riding the bike. Every time I would throttle up the engine would start sputtering. I thought maybe it was a carb or a fuel issue, but it wasn’t. The carb has been cleaned and rebuilt, clean gas in a relined gas tank every time. Now the bikes RPMs will randomly increase and decrease without touching the throttle. The same issue I had before.

now I have tested the voltage regulator/ rectifier, the stator, and the battery and all are just fine. It is definitely an electrical issue. I am stumped. Any help would be greatly appreciated!

ps. The voltage regulator is not the series one. It is the normal one that shunts the extra current to the stator.

[Kentman7]

Could it be my CDI igniter unit ?

[tom203]

This issue doesn’t sound electrical to me….tell us how you or someone cleaned the the carb. Sounds like pilot circuit is not operating properly….perhaps clogged…..so revs bounce around

[Kentman7]

Thanks tom203. Do you know what the pilot mixture screw setting should be? I know it comes pre adjusted with caps so you don’t try to adjust yourself. But previous owner was adjusting. I want to make sure they are to the right spec.

but the bike was having the same issues as last time, which were solve with a new stator and voltage regulator. When I’m out riding now, the RPMs with randomly increase, far past the RPMs of a normal idle.

as far as the carb goes, it was cleaned and rebuilt by a trusted mechanic. The petcock filter was clean. And the bike has got clean fuel in a relined gas tank with sea foam every other time since then.

[tom203]

”but the bike was having the same issues as last time, which were solve with a new stator and voltage regulator.“

Maybe then the ignition system was misfiring due to faulty charging/ connections producing erratic idling. But still sounds like carb/fuel issue or air leak at cylinder head. Did you replace the carb boot o-rings?

https://www.partsoutlaw.com/oemparts/a/suz/50d3ee85f8700230d8b4b588/cylinder-head

the pilot screw mixture screw would be out about 2 to 3 turns off bottoming out IF all carb passages are clean.
CV style carbs are very fussy regarding cleaning.
make sure both cylinders are firing…hopefully your electrical issue didn’t upset the ignition box in the first poor running episode.