A heavier mass on the crankshaft carries much more momentum this momentum helps to keep the engine running at a steady RPM as you add load to the motor.
This heavier mass will help to spin over a higher compression motor when starting.
You could also try lowering the compression with a decompression plate and 2 gaskets and see if that helps to spin the motor over quicker so it doesn't kick back but you may loose a little power .
