THIS WILL NOT FIT THE LIFAN 138CC WHICH PEOPLE ARE CALLING INCORRECTLY 140CC'S... THE 140 REV CAM IS FOR LIFANS WITH 55MM BORE AND 59.5MM STROKE'S ONLY !! THE BCI REV CAM HAS 6.5MM OF LIFT COMPARED TO 5.2MM ON THE STOCK LIFAN 140 CAM,, AND OF COURSE MORE DURATION AS WELL... BECAUSE OF THE EXTRA LIFT YOU WILL NEED THE INCLUDED 200149 WIDER COIL VALVE SPRINGS.. (STOCK_SPRINGS_WILL_BIND) THE BCI REV CAM USES THE SAME 3 BOLT ON 25MM PATTERN SPROCKET AS THE STOCK LIFAN 140.. (AND SOME ZONGSHEN 108/110'S) THE REV CAM DOES AWAY WITH THE AUTO DECOMPRESSOIN MECH, SO THERE IS LESS TO GO WRONG, BUT IF YOUR WEAK IN THE LEGS I GUESS IT COULD BE AN ISSUE ?? COME ON AND BUCK UP..ha ha I AM TOLD THIS ALSO FITS THE ZONGSHEN 110 / OR 108 CC MODELS (DON'T USE THE INCLUDED SPRINGS ON THIS MODEL THOU) ____________________________________________________ OVER ALL LENGTH IS ABOUT 74MM THE SPROCKET SIDE BEARING OD IS 35MM THE INSIDE BEARING OD IS 32MM 200148/S1129 @ _ "73MM_LONG" LIFAN_140/150CC LIFAN_JINCHENG ZONGSHEN RACE_CAM 1/22S (200148) 73MM_LONG TEMP OUT OF STOCKYOU "MAY" NEED TO USE OUR 200149 VALVE SPRINGS WITH THIS CAM, IF YOU HAVE A 50CC OR 70CC STOCK TYPE HEAD 200148 CLICK TO COMPARE BCI REV CAM LEFT TO STOCK LIFAN 140/150'S CAM RIGHT CLICK TO COMPARE BCI REV CAM LEFT TO STOCK LIFAN 140/150'S CAM RIGHT CLICK TO COMPARE BCI REV CAM LEFT TO STOCK LIFAN 140/150'S CAM RIGHT YOUR HEAD WILL/SHOULD LOOK LIKE THIS WHEN THE SPROCKET IS REMOVED @ ..LIFAN_&_CLONE TOP_CAM_SPROCKET 28_TOOTH (290L)BIG HOLE IN CENTER IS 17MM 290L