1985 water pump questions

[490SS]

I recently took apart the water pump on my '85 CR500 and I found that the shaft has significant wear from the seal cutting into it:



It's not leaking yet, but it has me worried. Naturally, the part is discontinued from Honda.

Does anybody know if a later model water pump drive shaft will interchange? Anybody have a good used one for sale?


I also found some corrosion in the water pump housing. Very little, though, a few pin holes that I filled with JP Weld. This is the infamous magnesium cover, right?

I was wondering if I could paint the inside of the water pump housing with some kind of (epoxy?) paint to seal it off and prevent further corrosion? Sound like a good idea?


Also, there was some gunk in the cooling system, gel like stuff that dried to a scaly, powdery white coat. Should I run some cooling system cleaner through to clean that out? Will those automotive cooling system flushes work, or will they eat up the magnesium?

Lastly, what is the best coolant to run in these bikes in terms of corrosion prevention?


All my other bikes are air cooled ('82 Husky 430, '83 Maico 490, '84 CR500), this is my first water cooler, so please excuse the stupid questions...


Thanks!

[100hp honda]

i dont see nothing wrong with it . get small piece of sand paper and spin the shaft in there and put it back together with new seals. if your that worried i think the shaft from the newer bikes will work

[2strokekyle]

It appears you have a later model shaft already. The '85 has a metal gear not plastic. If the seal is not leaking around the shaft why mess with it?

[kelroy_leon]

I think I run a 90' shaft in one of my 85's. My 86' has a 90' cover on it. It is on here, $200.00 86'. I have seen 90' style covers for arounr $100.

[dannygraves]

the '85 had a steel gear, all the later ones were nylon. yours has been replaced at some point. I agree with clyde, install it in a drill chuck and run some very fine sandpaper over it. I've done that to 3 or 4 without any issues. I only ever replaced 1 because it has some really bad grooving.