Stil surging at idle

[timbrigham]

My 81 GS450L is having continuing carb problems. ..

Things sound a lot better but I'm still getting surging / hunting at idle. When I'm quickly decelerating I also sonetimes have my rpm drop to about 600.. I'm afraid one of these days it'll cut out.

I have replaced the seals between the boots and head, stripped down and chemically cleaned the entire carb assembly and replaced the adjustment screws. After the last round of changes I went around with carb cleaner and verified no vacuum leaks and adjusted the idle air screws back to 2.5 turns out.

Where should I go from here?

[tom203]

".....and replaced the adjustment screws. "

Does this mean you replaced the idle mixture screws? Replaced the carb o-rings?
the "surging " sounds like not enough mixture when the throttle is closed

[Guest]

Are the valves adjusted?

[timbrigham]

".....and replaced the adjustment screws. "

Does this mean you replaced the idle mixture screws? Replaced the carb o-rings?
the "surging " sounds like not enough mixture when the throttle is closed

Yes, the idle mixture screws and the o rings between the boot and the head.

With my reading it does sound like its running lean. I'm thinking something upstream from the carbs since I've checked them pretty thoroughly now. Maybe an issue in the petcock? Some issue in fuel delivery?

[Nessism]

Is the bike stock or modified? To mirror John...are the valves adjusted? How about vacuum carb sync?

[timbrigham]

Are the valves adjusted?

I haven't... should only have been a few thousand miles since it was done by the last owner.

[Nessism]

I haven't... should only have been a few thousand miles since it was done by the last owner.

Famous last words...

[timbrigham]

Is the bike stock or modified? To mirror John...are the valves adjusted? How about vacuum carb sync?

The last owner installed short exaust pipes. I installed some slightly larger ignition coils. I'm checking the sync yet this afternoon.

[Nessism]

How short? Are they open pipes? Pods? Any jetting changes?