XS400R Seca Engine trouble

[ctavel]

After cleaning the carbs on my 81 XS400R Seca I've gotten it to idle and rev pretty well. However its only running on one cylinder, the left. I have checked for spark and I'm getting a good blue one on both sides, so its not that. Fuel is getting to both bowls and I'm not sure how to determine if the combustion chamber is also getting that fuel. Also, if the compression was low on that side would it keep it from firing?

thanks in advance

 

[stevendefense]

I am currently having the exact same problem with a 79 XS400. At first I thought it was a bad coil but a test showed that they were both good. Then I thought it was the diaphragms but they are too expensive to just try without being 100% sure.

Earlier tonight I hooked up a smoke machine to check for vacuum leaks. The crankcase vent tube was leaking and I repaired that, but did not Have time to recheck.

Have you hooked up a vacuum gauge yet? if so what were the readings on each cyl. On mine the left side (running good) was right around 5 in/hg. The right side (not running well) was all over the place. This is what has pointed me to either a vacuum leak or a burnt valve.

Have you checked the compression yet?