[ShadeTreeMech]

I'm of two minds on this one. If you're accelerating and decelerating a lot, a lightweight flywheel "may" help. But I wouldn't consider a heavy flywheel in the same class as a parasitic drag, such as a power steering pump or alternator. The reason being, if you had a motor minus the head so the crankshaft and pistons could spin freely, and you compared how long the crankshaft spun with a heavy flywheel vs a lightweight flywheel, I bet the heavy one would win. Following that line of logic, it can't be considered parasitic drag if it makes the crankshaft spin for longer.

It may not be parasitic drag, but how much does it cost the engine in fuel to keep a heavy flywheel turning? I don't know.

However a motorcycle engine does not have a heavy flywheel of any sort (unless you go into Harleys) and they tend to do well on fuel. But they do require a higher rpm to idle smoothly and tend to require a bit more feathering of the clutch.

To s2k-takara I would wonder if having the more lively throttle response may have helped him develop more of a lead foot?

To autoteach, as right as you may or may not be (I haven't a clue) you could have been a lot more civilized and diplomatic for certain. Honey attracts more flies than vinegar and all that....