the harmonics are the same, as is the rev range. the old motor did have some valve train vibration at about 3200rpm but that was from the solid cam.
as for the other question, the old 8 and 10 counter weight cranks were fine for engines that only rev to 5500-5800 but if you miss a gear or get over excited you will shake the flywheel loose or put the balancer through the radiator. the ef 12cw is only good for higher reving motors that need to rev to 6000+rpm other wise a waste of money.and the stroke stays the same as 250cu
cheers.
as for the other question, the old 8 and 10 counter weight cranks were fine for engines that only rev to 5500-5800 but if you miss a gear or get over excited you will shake the flywheel loose or put the balancer through the radiator. the ef 12cw is only good for higher reving motors that need to rev to 6000+rpm other wise a waste of money.and the stroke stays the same as 250cu
cheers.
