FZ1riderNY
Moderator
The plugs are already out. Something valve wise has to be messed up. I'll wait on that manual and start tearing the heads off to inspect the valves probably. Idk what else I can check without tearing it apart more
I'd take a measurement of the valves on the good side for now and compare specs with those of the bad side. See what the difference is, if any. If the valve or valves on the bad side aren't lifting to spec, it may be a bad or bent valve stem which shouldn't be too bad to replace. You'd just have to re-seat them with a lapping tool and lapping compound.