THIS IS THE KIT WE HAVE BEEN WAITING FOR IT FITS ALL XR70'S, 1982 THRU 1994 CT70'S AND THE 1982 AND 1983 PASSPORTS. THIS MUST BE USED WITH THE STOCK HEAD AND CRANK. YOU WILL NEED TO MAKE CARB ADJUSTMENTS TO GET THE MOST FROM YOUR LABORS. THIS KIT WILL ALSO WORK ON THE 1982 THRU 1999 Z50R'S,AND ALL XR50'S "IF" YOU USE ANY 70 HEAD. 85CC_CYLINDER_KIT XR70 ALL YEARS CT70 82_TO_94 PASSPORTS (82_83) 1-9/1-37/2-10$129.95 51MM_BORE (63MM/SHORT) STEEL_CYLINDER (MARKED_49CC) (100009) 51MM_BORE (63MM/SHORT) STEEL_CYLINDER (MARKED_49CC) (100009) 100009$62.95 51MM_PISTON_KIT (NEW_70_HEAD) (LONG_ROD) (SHORT_CYLINDER) (100037)THIS WILL ONLY WORK IN OUR 51MM BIG CYLINDER STOCK HONDA CYLINDERS CAN NOT BE BORED OUT THIS BIG!!!! 51MM_PISTON_KIT (NEW_70_HEAD) (LONG_ROD) (SHORT_CYLINDER) (100037) 100037$59.95 TOP END GASKETS ** PICK BORE SIZE ** 39 47 51 52 MM tempTHIS 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 temp 200008 / 200009 / 200010 / 200011$13.99PICK_BORE_SIZE: 39MM_20000851MM_20001052MM_200011 HOW TO PUT RINGS ON THE PISTON L@@K