ok correct me if im wrong but these little babies provide the motor with more centrifucal force which means you can lug around without stalling better right?

Correct. They also improve traction because it slows how fast the engine can rev.

More rotational mass, slower to accelerate and decelerate.

Increases Inertia

my 68 BSA 441 had an amazingly heavy crank shaft assembly. (like adding huge fly-wheel weights)
i could dump the clutch at an idle in first gear and the bike would not stall !
LOVED IT.

down side?
whack the throttle open and the motor went from, pop,pop,pop to BANG,BANG,BANG, without increasing speed much at all..

LOVED THAT TOO.

http://en.wikipedia....ment_of_inertia

MOI = resistance to change in angular motion (ie how hard it is to make it spin faster or slower).

Increasing mass increases MOI which means it's harder to stop the flywheel spinning. Simple!

daled said:

great anaolgy, LOL. I had a 500 husky with a (stock) heavy crank and flywheel that you could dump and it would just lay there on the ground and wind up all the local vegetation in the rear wheel and sprocket, didn't stall though.

My crf250x runs the heaviest one I could find. Took away that "snap" that made it easy to lift the front wheel on a throttle wack. Now i have to lightly touch the clutch, but when i do the all that stored flywheel energy picks the wheel up even farther.