KX 500 water pump problem

[Hogwylde]

anyone know how to get the H2O pump drive gear off the end of the crankshaft? It looks like it's press fit in, but there is no way to get ahold of it to pull on it. Since it's toast anyway, I'm thinking of having a bolt welded to it and putting a deep well socket over it and threading a nut down as a make shift puller. That is IF it's press fit in there. If it's threaded.....I'm stumped!

 

[Hogwylde]

anyone?? anyone at all have an idea?

 

[Rider 007]

It's been a while since I looked at the primary end of the KX5 crank, but I seem to remember that gear has a shaft on it that fits into the end of the crank. Obviously, something would have to cause it to rotate with the crank, so it must be coupled in some way. If there is no flat side to the shaft, pin through it or other externally visible means of coupling the two components, it seems logical that it might be a press fit and may even have a locking agent applied. Find a parts schematic to determine if it's threaded but I don't believe that it is, as I don't know what you would use to torque it.
If after removing the primary gear you cannot grab the backside of the drive gear with a puller, you may be able to drill the center and insert an extractor or, as you suggested, weld another piece to it to allow you attach a makeshift puller or a gear puller with a slide hammer attachment. Heating the end of the crankshaft while pulling the gear should ease removal by expanding the ID of the hole in the crank that the drive gear shaft is in and reducing the interference fit (and would also help break down any locking agent).

Hope it helps, let us know how you make out.

 

[Hogwylde]

Attaching a puller to the end of the gear only resulted in snapping the gear off and leaving the shaft in the hole.
Removal was accomlished using drill bits and a carbide cutter bit for a Dremel. That case hardening is pretty brittle once all the soft inner metal is removed.

 

[Rider 007]

Sounds like they had a locking agent on it.
Glad you got it out, though!

 

[Hogwylde]

Nope, no locking agent. It's that TIGHT a fit. I was nervous hammering the new one in. Gentle taps weren't getting the job done. Whacking it HARD was needed to get it to move into place!
I'm definately NOT worried about it coming out or loose without any locking agent.

 

[Rider 007]

That being the case, heating the end of the crank that it fits into while cooling the shaft of the gear will decrease (and possibly eliminate) the interference fit between the two parts. This would make it much easier to assemble and reduce the chance of damaging the part if it was driven on instead of being pressed on.
Back in the 70's we used to heat the cases of our YZ's in the oven while freezing the bearings. You could drop them right in. We also used to heat the cases to remove the bearings. We knew they were done when you heard the bearing fall out onto the rack!
Thanks for sharing the info as it will probably make someone else's life a lot easier when they face the same problem.

 

[apx5777]

Hi, this is my first post here,
I've got the opposite problem. The water pump drive gear shaft is loose on the end of the cranshaft with about a 1mm gap all round. It was so bad that when took the clutch cover off it just fell out. I think I might need a sleeve making to press fit it into and then that into the crank. Has anyone else had this happen? I've checked the parts diagrams and the Clymer manual and there is no mention of a sleeve.
(1987 KX 500)