WHY BORE YOUR OLD CYLINDER?????????? USE IT FOR A FISHING WEIGHT, OR A PIN/PENCIL HOLDER. WITH THIS KIT YOU WILL GET EVERYTHING IN THE PICTURE. CYLINDER - HONED AND READY TO GO-, PISTON,PISTON RINGS,PISTON PIN, PISTON PIN CLIPS AND A TOP END GASKET SET. JUST BOLT-ON AND GO. THIS KIT IS TO BE USED ON ANY Z50A OR R THRU "81" ENGINES. THIS SHOULD BE USED WITH THE STOCK 50CC HEAD. THE CYLINDER SAYS 49CC ON THE CASTING. 1-7/1-76/2-8$95.95 39MM_BORE (63MM/SHORT) STEEL_CYLINDER (1P39FMB/100007) * * * ALL NEW CASTING WILL WORK ON THE FOLLOWING STOCK 39MM X 41.4 BORE AND STROKE ENGINES ALL Z50'S 68 TO 99 ALL XR50'S ALL CRF50'S ALL LIFAN 50'S 39MM_BORE (63MM/SHORT) STEEL_CYLINDER (1P39FMB/100007) 1P39FMB$39.95 STANDARD PISTON KIT ALL_Z50A'S (100076)SO FAR STANDARD IS THE ONLY SIZE WE CAN GET THESE COMPLETE PISTON KITS IN. THESE WILL FIT 69 THRU 78 Z50A'S YOU GET THE PISTON, PISTON RING SET, PISTON PIN AND PISTON PIN CLIPS WITH THIS KIT. WILL ALSO WORK IN 1979 TO 1981 Z50R'S 100076Regular price: $21.99Sale price: $18.95 TOP END GASKETS ** PICK BORE SIZE ** 39 47 51 52 MM THIS KIT HAS EXTRA PARTS YOU WON'T USE,, THIS WAY IT WILL WORK FOR DIFFERENT MODELS. FYI STOCK 50'S = 39MM ALL Z50A Z50R XR50 CRF50 = 39MM ALL XR70 CRF70 = 47MM CT70 ALL = 47MM ATC70 ALL = 47MM C70 PASSPORTS ALL = 47MM C70M'S ALL = 47MM 85CC KITS = 51MM 88CC KITS = 52MM TRX90 = 47MM TRX90 103CC = 51 TRX90 106CC = 52 THIS WILL WORK FOR ALL YEARS OF 50'S 70'S AND TRX90'S PICK_BORE_SIZE SEE DROP BOX BY ORDER BUTTON 39MM_ 200008 47MM_ 200009 51MM_ 200010 52MM_ 200011 TOP END GASKETS ** PICK BORE SIZE ** 39 47 51 52 MM 200008 / 200009 / 200010 / 200011$13.99PICK_BORE_SIZE: 39MM_20000847MM_20000951MM_20001052MM_200011