www.zxrworld.co.uk

Does anyone know how the water pump is driven?
Cheers Matt

it connects onto a shaft from the oil pump, the oil pump's connected to the clutch basket (i think) and the clutch basket's connected to the crank.

Cool think the water pumps broken then. Took the housing off and and can turn the blades around.

Is it a big job to change it?

It's too cold to venture into the garage, so my comments should be treated with caution. But since you have removed the cover to access the blades, then the body of the pump can just be pulled out of the crankcase. If not, then there are two long bolts securing it in place. Note that there is oil the other side, so it may be advisable to not have the bike on the side stand, but rather lean it against a wall the other side. Just compare the level of oil in the sight glass on the clutch side with the level of the pump body. There is an O-ring round the housing to seal it. The blades are connected to a shaft having a slot, which engages with a on the drive shaft. When you install the replacement pump, hold the body and turn the blades until you feel the slot meshing with the . I can only think that the blades have slipped on the drive shaft. This is not the weather to be messing with cold metal!