ALL THE CT70 AUTO'S HAD A 15 TOOTH FRONT SPK. STOCK. THE 4 SPEED CT70'S HAD A 14 TOOTH STOCK. STOCK ON THE ATC70'S 73 TO 81 MODELS HAD A 14 TOOTH AND 82 TO 85 HAD A 13 TOOTH FRONT SPROCKET. BUT ANY OF THESE SPROCKETS WILL WORK ON YOUR CT OR ATC 70, IF YOU WANT TO CHANGE THE GEARING. ONE SPECIAL NOTE THIS 12 TOOTH SPROCKET (24J) WILL REQUIRE THE (79K) LOCK PLATE. PASSPORTS TAKE A 14 TOOTH FRONT SPROCKET AND OUR #(24K) FRONT LOCKING PLATE. one customer said: "And just for info, the 17 tooth sprocket does fit the Passports and makes a noticable difference. Not as much power at start but surely enough to get you started and then in top gear a much more reasonable engine speed. Thanks again and I will order from you again." #_OF_TEETH 12T__24J 13T___(17A) 14T___(16i) 15T___(14C)66mm_OD 16T___(209M)71mm_OD 17T___(209P)75mm_OD 06-SPK$7.97#_OF_TEETH: 12T__24J13T___(17A)14T___(16i)15T___(14C)66mm_OD16T___(209M)71mm_OD17T___(209P)75mm_OD *LOCK PLATE FR SPK Z50R'S_82_TO_87 ATC70_82_-_85 TRX70_ALL (79K)FOR USE WITH THE 12 TOOTH CT70 SPROCKET !!!! 79K$1.50 *LOCK PLATE FR. SPK. CT70_69_-_94 ATC70_74_-_81 Z50R_88_-_99 (24K) THIS PLATE KEEPS YOUR "STOCK" FRONT SPROCKET FROM FALLING OFF OF THE CT70K0 THRU 94 ,, ATC70'S 74 THRU 1981,, Z50R'S 1988 TO 1999 AND THE XR70'S THRU 1999. 24K$1.49 *BOLT_FRONT SPROCKET LOCKING_PLATE FITS ALL BUT(6x8 MM) (Z50 81 AND OLDER) (53D) THIS BOLT WORKS WITH OUR #24K AND #79K LOCKING PLATES. SOLD EACH, OEM HONDA BOLTS YOU NEED TWO PER BIKE. WILL ALSO FIT ATC AND TRX 70'S BOLT (53D)$0.63