GSR40 GSR40TSI Genuine Zenoah Piston as used in the stock version and the famed Trevor Simpson version of the GSR, the Trevor Simpson Interceptor (TSI). The piston is one of the first items top tuners modify to get more horsepower out of their engines.
These are the very same pistons used at the World Finals Goped Races over the years.
Renew that old engine with a fresh new piston.
Piston for Zenoah G43L-D engine. PMW part # 4712