Ever balance a crank? If you have, you’ll know a zero balance flywheel bolted to a balanced crank WILL change the balance. Every time. The question is, how much does the balance change when you bolt the flywheel on.
It depends. If you make the flywheel zero it’s still never zero. And the weight is further from center by far than the crank weights.
So a few grams on a flywheel becomes much greater when it’s bolted to the crank. Now, add the disc and pressure plate and you have a hot mess.
