I would think cranks can also be balanced so it will run smoother @ high RPM & run a little rough in the lower RPM range.
I'll ask Dave @ "The Balance Shop"
When I used to road race a two stroke GP bike & other 2 stroke engines,I keep on breaking cranks because the class made us use the stock heavy flywheel.
I had my friend Dave @ The Balance Shop ,balance the crank so it would run smoother @ high RPM ,,& it did just that,a lot smoother & just pulled cleaner all the way up to 13,000 RPM,eventually the crank still broke,but it did last longer than w/a stock crank & with stock/original balance.
Originally the engine turned to 8500 RPM,& the crank would last a full season.
MBHD
