This 56 mm piston gives 123 cc.
The piston has two 1 mm chromed steel rings that are much stronger than the original 3 mm cast iron rings.
The piston pin is moved up 1 mm to give the same scavenge ports duration as the Sport cylinder and the scavengeports in the piston is 2 mm higher.
The pistonskirt is 4 mm shorter for increased inletport duration.
The piston dome is 3 mm lower to lower the weight and compensates for the increased compression with 1 mm overbore.
Modification, Porting and Mounting instruction will be included with each piston.