One of these carbs is not like the others...

OK, It's obvious that the previous PO had the carbs apart for a rebuild or something and re-installed the bowls on the wrong carbs. But.. I'll bet he used standard carb rebuild kits which have bowl gaskets without the provision (covers the valve) for the check valve for the pump. ALL carb kits for these carbs are labeled 77-78 and they don't make any for 79-81. You must use standard kits (can use 90% of parts) and must get seperate bowl gaskets and "O" rings for the check valves. What I'm saying is that if the pump is disabled it does not matter which bowl goes on which carb and the little nipples which were for fuel transfer from the pump to each individual squirter are now useless. These carbs came with 97.5 jets (102.5 standard) or less and needed a squirt of gas to avoid a hesitation upon throttle opening. If the PO blocked these and the pump is disabled you now have a set of regular 650 carbs but with the leaner jetting. I would remove carbs and check jetting, if they have 90 something jets just install 102.5's and your back in the ballpark. I have these on my '80 F1 and disabled the pump and installed 102.5 jets. I have a set of standard '78 carbs that I might rebuild and install. They are a lot easier to work on for sure.

Here is the bowls with the check valve (top)



The special gaskets required

Get a can of carb cleaner and clean the crud off. Ride the bike and see where the bike is comming from.

I always disable pumps on these carbs. Roy

Hi Sparkn, It looks as if the PO had switched number 2 and 3 carbs when he put them back together. It seems he took the diaphragm off and removed the linkage for the pump. If I were you, I'd put some tubing on the nipples that go between the carbs, so no gas could splash out and also it will keep the bowl from evaporating any gas. Many guys disconnect the linkage instead of doing a repair. It won't hurt anything. Bob

Thanks for all the input. I'll make this one of my winter over projects. Might have to make this bike a hobby. There goes my fund for the new RC helicopter I wanted. Maybe I can raise the rent on the son that refuses to "launch".