1982 gs750 running on 3 cyl under low throttle

[Guest]

Hello, as I was riding my bike (1982 GS750T) today one of the cylinders stopped running when I have the throttle only just cracked. Once the throttle is open past a certain point the bike runs on all 4 cylinders and makes full power. Anyone have any experience with something like this? I'm thinking a fueling issue because I've only got one tank of gas run through it since taking it out of storage (and I neglected to put fuel stabilizer in it for the winter , I did start it periodically though), but I figured I'd ask for another opinion.

Thanks!
-Len

[tom203]

One of your carbs likely has a gummed up pilot circuit. - the one that it mostly runs on at low speed- so it's not supplying enough mixture. Leaving untreated ethanol gas in tank during months of idleness is asking for trouble.
try running fuel cleaner in with gas for first couple of fill ups. Find some long downhills where you can get up to speed then close throttle quickly to put some " load" on the pilot circuit. You might get lucky - otherwise carb cleaning fun awaits.

[Steve]

A gummed up pilot circuit is a likely suspect, as tom203 suggests, another suspect would be "carb sync".

If that one carb is simply not opening as soon as the others, the bike will, indeed, run on 3 cylinders.

.