Scooterotica

Probably been covered before, but I'm building a 200 Rapido Classic and have the choice of Std 3 ring asso piston and a 2 ring asso with the inlet skirt shortened by 3mm. Will be running 42mm clubman, 25mm phbh through the airbox with std SX200 gearing. What benefit or disadvantage does the shortened piston give and how noticable would this be in "real world" conditions?

The full length skirt it will give you lower inlet timing which is more suited to the 25mm carb.I think with the Asso 2 ring you would end up with @155 deg on the inlet which is more suited to big carbs and lots of spit back at low revs.If you don't want the 3 ring piston there are 2 ring available with the full skirt (Mahle/Escort)

Cheers for the reply, I'll stick with the 3 ring by the sound of it, I know someone building an Indian stg 4 with 30mm dellorto and jl3, sounds like the cut piston will be better suited to this.