Hebo Manston Replica Replacement parts

I recently purchased a Hebo Manston Replica 68cc (HR4000161N) kit for my Keeway Hurricane 50 (Minarelli Horizontal 12mm). It ran very well for about two weeks. Then the power dropped considerably, the engine stopped running and will not start. I think I might have jetted the carburetor too lean. Now I need a replacement piston set and gasket set.

Can anyone tell me which parts to order to fit the HR4000161N kit?