89rmx250

Member
Feb 10, 2000
25
0
I have an 89 RMX250. I replaced the water pump bearings, seals, and shaft last year because of a leak. Now I just got another milk shake out of the crank case. It lasted for a year of some long hard trail rides, but that sure seems short. Shouldn't a repair like that last for many years? Could it be that I had some stuff in the water that started the leak again? I only used distilled water to mix into the radiator.

Thanks for any help!
 

RM_guy

Moderator
Damn Yankees
LIFETIME SPONSOR
Nov 21, 2000
6,944
174
North East USA
What is the condition of the radiator? It sounds like there is crap in there (from corrosion, etc) that is abrading the seals. Are you using a quality antifreeze for good lubrication?
 

89rmx250

Member
Feb 10, 2000
25
0
The radiator is good and has been flushed. I just now drained it to remove the clutch cover and all looked good. There was nothing that could be seen in the anti-freeze.

If the main bearings are starting to wear, could this be felt in the pump shaft causing the seals to wear out quickly?
 

spanky250

Mod Ban
Dec 10, 2000
1,490
1
Are you using auto antifreeze that contains silicates? If so, that can be the cause of the leaking seals. Choose a brand of antifreeze that does not contain silicates.

If the main bearings had enough play in them to cause enough runnout to prematurely wear out the water pump seals, then it would certainly have worn out the crank seals as well.
 

89rmx250

Member
Feb 10, 2000
25
0
Silicates???

Yes, I checked and I was using PEAK (with silicates). What effect does this have on the seals?

The shaft had three groves worn in it. I polished it with emery cloth down about .001 and the groves are just about gone (real smooth). Local shops have the two seals and gaskets but not the shaft (going up the Continental Divide Sunday ;) ).
 

wanrep

Sponsoring Member
Aug 21, 2001
39
0
Silicates is sand. That's the additive that cleans your car's radiator.
Goldwing riders had a rash of water pump seal problems that was attributed to the silicates in automotive antifreeze.
Pick up a bottle of Honda HP Coolant or Suzuki's equivalent to refill your radiator.
 

RM_guy

Moderator
Damn Yankees
LIFETIME SPONSOR
Nov 21, 2000
6,944
174
North East USA
I’ve been using PEAK for years with no problem. It is one of the few coolants that are magnesium friendly. If you recall, they used to sponsor a MX team.

When you change the seals, change the shaft at the same time. The diameter of the shaft is critical to proper sealing and if you polish the grooves out you are reducing the diameter.
 

wanrep

Sponsoring Member
Aug 21, 2001
39
0
Don't forget to grease the inside of those new seals when you reassemble.
If it's put together dry, it'll wear prematurely.

As far as running auto antifreeze, it wouldn't matter if you're going to rebuild the motor after every weekend like the factory guys do.
 

cw242

Member
May 17, 2000
37
0
seal failure

my buddys cr 250 had the same problem, his would only last about two months, if you look closely at the spring around the seal it can be tightened with a small screwdriver,this solved all of his problems, apparently they just came with too much slack from the factory...good luck cw
 
Top Bottom