The discolored areas
on this flywheel were caused by excessive heat. The flywheel must be ground to
remove these hardened crystalized areas. They will cause clutch chatter and grabbing
if they are not removed. DO NOT try to resurface a flywheel on a lathe. A lathe
tool will jump over the hard spots while it cuts into the softer cast iron surrounding
the spots. The flywheel must be referenced off the crankshaft mounting surface
in order to cut any runnout off the face. This cannot be done on a lathe. A flywheel
surface grinder is the best machine to use for this purpose.