two months of work and...

[Guest]

Have put a lot of work into this May aquired 80 gs550. I'm at the point where the bike rides pretty well, but I'm stumped a couple things.

The bike starts up fine, but 3 is cold at idle and 4 isn't as hot as 1 and 2. After riding it for awhile all the pipes are hot.

Also, it doesn't idle well after warm up. I seem to have to lower the idle screw just to get it to come down to 2K or so. If I catch it with the clutch a little it comes down, but typically ends up stalling if I don't roll the throttle a little. Bike is sometimes hard to restart when it's hot.

Valves shimmed to spec
All new gaskets
Compression 120 or better
spark on all 4
Carbs dipped for 24hrs each and new o-rings
New o-orings and clamps on intake boots, boots inspected
float levels around 22 mm
plenty of gas getting to carbs
air screws 3.5 out
bench-synched
no mods so far as I can tell except for a k&n air filter

I've got a vacuum gauge set in the mail, and the sync is the last thing I can think of doing. Could out of sync carbs cause the dodgy idle? What's going on with 3 and 4?

[salty_monk]

I think it could, from what I've read on here a bench synch is only really to get the engine started....

Good luck!

Dan

[chef1366]

I think the sync will set you straight. :-D

[$hitfoot]

bad coil on 3 and 4?

[smagnusen]

No, coils are split 1-4 and 2-3. Plus I'm getting a spark.

[Nessism]

3-1/2 turns out on the mixture screws sounds a little too far, usually the setting stops affecting the idle after 2-1/2 turns in my experience. Not sure this matters but thought I'd throw it in.

[rustybronco]

3-1/2 turns out on the mixture screws sounds a little too far, usually the setting stops effecting the idle after 2-1/2 turns in my experience. Not sure this matters but thought I'd throw it in.

That is what I thought yesterday so I went and looked it up, 3.5 turns is correct. doesn't mean it's ideal though.