Issues with Cylinder 3, Vaccum leak?

[mortation]

I am having an issue with Cylinder 3. It doesnt get as hot as the other 3 and I get some sputter/backfire out of my right pipe.

Seems to run OK when the bike has been on the road for 15+ minutes but still sputters on sharp deceleration. I am thinking it is probably not related to coils, the problem doesnt appear move when I change the coil wire.

Valve gapping is write. Dont think it would be a timing issue. Has good compression so not likely a valve issue.

So I am thinking it may be a vaccum leak some place in the carb, a T perhaps? The boots and clamps are all new on both sides so they are not leaking. New air filter too.

Any thoughts or suggestions? I was thinking about cranking up the Fuel/Air screw just on #3 but I bet that will just hose my plug :P

[mortation]

Crap :P Wrong Forum.

[simon kuether]

#3 pot running cold

sounds like you are missing a hose from #3 carb to back of your fuel tap (petcock ). I bought a '79 gs1000s (real deal) and previous owner(s) had removed it . I couldn't get it running properly & had same symptoms as yours. I left it off, blanked off both carby and fuel tap with short pieces of fuel line and zip ties. Boom boom , job done.

[thewiz]

Mortation,

I am no expert but make sure you check this first since it happened to me. Check the resistance in your spark plug wires with and without the caps. Mine was doing the same as yours and the cap had shorted. Long shot but a $5.00 fix if that is all it is.