Waterpump shaft end play

[SpeedyManiac]

I'm getting a funny noise from my engine and trying to diagnose it. It may be piston slap, but I'm checking the simple things first before I pull the cylinder. I pulled off the waterpump cover and noticed my impeller had been rubbing on the cover and that there was around 1/8" end play in the impeller. This seems like it may be to the source of my problems. What is the spec on the impeller shaft end play?

Also, I'm going to pull the right side engine cover to check the powervalve governor. I've pulled the water pump cover and impeller off, removed the kickstarter and knuckle and all the bolts holding the engine cover on, yet the bugger doesn't want to come off. Any tips? I pulled the clutch cover off, but didn't remove the clutch since it looks like the cover fits around the clutch.

[GMP]

You don't need to pull the waterpump off, or even the cover, to remove the side case. Its a unit in the side cover, the drive gear just slides off the crank pinion. Some waterpump cover bolts and clutch cover bolts are through bolts however that fasten the side case. I suspect you missed a bolt.

I don't know if there is a spec on axial play but I know that 1/8" sounds like a problem especially if the impeller is hitting the cover. Consult the drawing, the water pump gear is plastic and keyed to the shaft with a pin. I would guess that this is broken or the bearing has totally failed allowing that play. I think at one time someone had a shaft fail where the pin was pressed in. It will be obvious when you get the cover off.