This Crankshaft Pinion Puller is necessary to remove the crank pinion (timing gear located on one end of the crankshaft) from it's home in the right hand crankcase. This is necessary to split the cases for a full rebuild. This puller will work with all Triumph pre unit and unit twins, 650 c.c. and 750 c.c. and OIF Triumphs and Norton 750 and 850 motorcycles. Direct replacement for Triumph and Norton OEM # 61-6019, A121, 06-7524