Has any one lightened the flywheels if so to what result?
It has come up in conversation with a few wm20 owners . I don't think it would be a grate advantage to make the engine rev quicker & higher as I think this would be the only result.
I am not sure that it will increase the horse power.
I am also concerned with the bike, due to the drive train that is not designed for it, as well as the loss of toque from the engine.
Regards
Michael
email (option): michael@nammech.com.au
Hi Michael...Drive train problems are not an issue at all with the M20 even when tuned..However, there is not much benefit to be gained in lightening the flywheels in a standard M20 engine.It has little or no effect on overall power produced, though it does help you to get to the same place a bit more quickly...Also once you have removed material the flywheels need to be rebalanced.
Being 'over endowed' with flywheels the reduction in flywheel effect is also minimal in a practical sense, unless a substantial amount of material is removed.
I use M20, B31 and B33 flywheels in tuned OHV engines and in that case they need to be radically lightened to enable the engine to take advantage of port, cam, carburation and other improvements...in fact it is a key requirement to producing power in these engines....
In the case of the sidevalves, enlargement of the cylinder capacity and some mild headwork and port work is the way to produce a bit 'extra'. As they are basicaly a stationary/industrial engine with a wheel on each end extensive work is required to extract a lot of extra power....Ian
email (option): ian@wright52.plus.com
Thanks Ian
I did not think it would be the quick answer in the horsepower hunt.
I have enough parts for a second engine and was going to look to fit a m21 crank & rod , as well as a larger piston, then look at the head flow.
BUT I think I should get my bike finished and on the road first 
Before I look at tuning the engine.
Thanks
Michael 
email (option): michael@nammech.com.au