yamily

Hi Nysmansx400. I bought an 1980 xs400 a couple of months ago. It wasn't running when I got it, but after rebuilding the carbs and adjusting the valve clearance, it is at least running. But I've got the same problem: starts up and idles, but cuts out when throttle is applied. I'm guessing it is running to rich, but making adjustments to the pilot screw (aka air/fuel screw) has changed the problem, but not really solved it. Now it doesn't die, but will rev too high... If I make any more progress on getting this tuned, I'll let you know. Good luck! The service manual does offer many clues!

Hi there. I bought my first motorcycle a few weeks ago - a XS400. Previous owner had said it was running a little rough a few years ago and took off the tank to do some maintenance... and never finished the job. After cleaning out a strange green gunk (is that what gas looks like when it is 2 years old?) and rebuilding the carb, got it started after many tries. It is running pretty rough, and hesitates when revved. One cylinder doesn't seem to be firing (one exhaust pipe is cold), but it does have spark. Seems to be getting fuel... as gasoline sputters out the tailpipe on that side. So... I've got some work to do.