Now unfortunately no piston 4 Puch and the only thing that I even have that's even close to a 42 mm piston would be Wide Open port Puch hero kit which is 43.5 millimeter I think off the top of my head but I already have two cases carved up for it one at Tomas an e 50. O bunch is of case halves for Tomas and batavus a few 505 bottom ends