vroom1776 wrote on 12/31/69 at 16:00:11:mpescatori,
A heavier flywheel? Why? Will this make it run smoother? A gearhead friend of mine suggested that the flywheel could be lightened to hot-rod it (not realizing I was talking about a single).
Your comment is not wrong, but there are buts.
A lighter flywheel is OK for 4+ cylinder engines, as they rev very very high and the flywheel is sometimes needed only for the starter motor and to smooth out at idling. However on a big single a lighter flywheel would make idle lumpier and at high revs it could actually be prone to more vibrations.
A heavier flywheel, on the other hand, would make idle much smoother, would imply less rev drop (c/o piston compression etc.) at gear changes and much more engine brake when downshifting. If one is to cruise on a perky engine, rather than lap around a circuit, I'd go for a heavier flywheel.
Actually many modern singles have one flywheel AND two smaller flywheels that rotate in the other direction !
Anyway, weren't we talking about carbs
Maurizio