On my 99 VZ800, I broke the water pump while dismantling the engine. I bought a second hand one from a bike breakers and it's shaft is 17511-48E00 rather than 17511-48E01 which is the part number of the original. The replacement doesn't have, what is referred to as a 'discrimination' groove in the parts catalogue, on the shaft towards the end where it couples with the oil pump shaft. This appears to be the only difference.
Does anyone know what the groove is for, and if I am able to replace a groove shafted waterpump with a non-groove shafted waterpump.