Cylinder quites firing when weather is cool

[dcb]

I have 1980 GS750 and it runs great in the summer. Whenever it starts getting cooler about 60F one of my cyclinders start cutting out. The plugs are about 6 months old. Could this be something besides a spark plug problem?

Thanks,
David

[focus frenzy]

even warmed up?
if it starts cold missing on one cylinder the choke circuit may be clogged.
vacuum leak is also a possibility.

[Dave8338]

Sounds like you're running lean on that cylinder...I had the same issue only on two cylinders and that was after a complete carb soak and rebuild, all new o-rings and gaskets and hours of checking for leaks. If you've not done all of this first, it is a must. To get rid of that issue on mine, I ended up bumping the jet needles 1/2 a notch using small washers and the problem is gone.

[dcb]

Thanks for the replies. I will checking it out soon.

David