Stroker crank over race full cirle crank ?

Well I've got a Pmtuning crank in my bike at the moment, But I'm looking to build my stage 6 racing engine (Waiting for MkII for Piaggio), What would be the advantage/dissatvantage to buying a stroker crank ? I know that the ports will have to be changed on the kit, But What do people mean by milling the cases ? Is it just general flow work and widening the transfers of do you have to have the bearing seats milled or something ?

 

Large stroke 50cc cranks don't actually fit in the cases. The crank webs are larger. Generally on 50/70cc etc what happens is you lose RPM's which is how they make their power so it's a bad idea unless your kit specifically needs one.

 

Alright cheers