Peter Ronney
XS400 Enthusiast
Hi everyone! I recently got my 1978 XS400 running after sitting for 2-3 years. I've been driving it a little but I can't help but notice the left cylinder fires intermediately. It smells like a wayyy too rich mixture coming from the pipe, the plug is black with soot, and the exhaust pipe doesn't get as hot as the right one which fires fine. My buddy has been working on his XJ650 and recently needed to change his plugs out for 0 resistance ones, he actually had a similar problem where two of the cylinders were firing intermediately. He has electronic ignition on his bike whereas mine has points. Could this be a source of error? What resistance plugs and caps should I be using? Could the mixture be off and if so how could I adjust it? Could it be valve gaps? Or something else?