Hey...I obviously have a water leak that's causing my crankcase oil to turn milky white.

I'm assuming it has to be my water pump shaft seal that's leaking.

Anyone have any experience replacing the seal behind the plastic impeller?

Oh yeah...it's a 2001 Beta Rev 270.

Bike runs great...no other issues that I can think of...plenty of power so I know it can't be a leaky cylinder base gasket.

Check your case around the water pump while your in there.

Hiya,

I have changed them before on my 03, I assume it will be very similar on the 2001, if not the same.

As rlracer says, some betas do suffer from corrosion problems behind the impeller if the correct coolant isn't used.

If you pop your water pump cover and the impeller off it will be obvious if this is the problem, if it is then a new case, welding or some araldite may be the answer.

If it is just the seal that needs changig, then this isn't such a big job really.

I seem to remember that I had to take the whole side casing off, although now I can't remember why, so you will need a new gasket to go on that caseing, try to get a paper type one, the others have tendancy to wriggle out.

Drop the oil first, and lie the bike on its side, once the case is off it will be pretty obvious how it works. You'll want to change the shaft, seals, and since your bike is a few years old, it might be an idea to change the two bearings as well. Once the shaft is out then everything should come out of the hole reasonably easily with gently applied force from a small hammer and punch, just try to to damage the casing.

When you re-assemble it will, and should be a very tight fit to get the bearings and seal in.

Don't forget to make sure that the gears are aligned when you put the case back on, you'd be surprised how easily it is to break those nylon gears if you try to force them back on and they aren't aligned. Smear a little grease on the gasket and make sure the faces are smooth and clean, I use a razor blade to shave any remaining gasket material off.

oh, and don't forget to drain the coolant first by removing the drain screw on the side of the impeller casing, and then undoing the rad cap.

Shouldn't be too bad at all.

.......

I'm assuming it has to be my water pump shaft seal that's leaking.

.......

Yup, probably the case gone, whip off the cover and have a look. If the case is in bad condition then replace it, otherwise go the seal. Be sure to get an identical seal, I tried a generic size that was slightly thicker and didn't work. The genuine ones are relatively cheap and better.

About repair with araldite - you should pursue a high temp adhesive I do not recommend it the 5 minuute Araldite as it softens above 65 C (check the website) and the ultra strength araldite softens above 100C, which is still a bit close for comfort in my mind. Also compatibility with a ethelyne glycol (coolant) is an issue for a lot of adhesives.

Good news is that Beta have mass produced the side case in recognition of the corrosion issue, so replacement price is not too bad.

Anyway, 'av a good go at fixing your milky oil issue because it affects performance, consistency and lifespan of your clutch, and gears.

Cheers,

Chris.

Nothing wrong with the case...looks just fine to me. I can't find any corrosion to speak of.

I think it's just a seal issue. I thought for sure I could just pry out the seal and tap a new one in? So I need to remove the side cover to do this, eh?

Thanks for the help gents!

Nothing wrong with the case...looks just fine to me. I can't find any corrosion to speak of.

I think it's just a seal issue. I thought for sure I could just pry out the seal and tap a new one in? So I need to remove the side cover to do this, eh?

Thanks for the help gents!

Yeah, the seal that causes problems is the one around the water pump, and usually the corrosion in behind the water impeller. so it's worth having a gander there, anyway. To see behind the impeller i'm pretty sure you need to remove the case. no big job, you can even leave the oil in, just lay the bike on it's side. You will have to pop the bash plate off at one end, unless you have never touched the bash plate on an obstacle...

Good luck!