- I have a 1970 Yam R5. I´ve seized it twice but never fouled a plug. Anyone know if there is a piston from something else that will work in this bike. NOS Pistons are too expensive. - I also have some RD engines and think I´ll fix up one of those if I can´t find reasonable priced pistons. I could use another gear anyway (RD´s has 6 speed trans.). Work Email: Richard_A_Jamieson@Dresser-Rand.com