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i have a 99 yz80 motor mounted on my shifter kart and the kart runs great but the last time i was riding it i noticed it was leaking oil down the side of the transmission casing and i looked closer and it was missing one of the bolts that held the casing and the water pump on so drained the fluid out the transmission and it was a really white milky color soo i figured it was water leaking from the pump mixed in the oil since the same bolt was holding both on so i replaced the bolt put some new fluid in it and took for a ride and i drained the fluid when i got back and its still a milky white color..although this time it was as bright of a white but it was still white..is it supposed to do that or no?...have any ideas? i have an event coming up in a week and i need it fixed but im out ideas of what it could be..

You have a few bolts on the water pump - one came off, so there's a chance that the gasket is shot, or the pump housing itself has warped (Or something else that the bolt was supposed to be holding) You might have to take the engine apart to look for the likely culprit.

It's also possible that the leak is coming from the head gasket or the cylinder/case gasket. If the leak is there, you'd probably smell burning coolant in your exhaust (Unless you are running water, which you wouldn't smell at all)

Maybe Buzz will chime in with something I might have overlooked

Give it another flush or 2 and see if it clears up. If it doesn't , chances are good that the seal is shot. It is a cheap, simple lip seal and not all that relaible. You have to take the impeller/shaft/drive gear out so that means pulling that sidecover, but it's not that hard. Just be sure you use new gaskets for the sidecover and waterpump cover. And have a service manual handy, it will make the job much easier.

It probably isn't a head or base gasket, on 2 strokes the coolant only gets close to the oil in the waterpump.

ok ill order some new seals thanks guys

Todd wrote:ok ill order some new seals thanks guys

No problem, BUT.....

The normal progression of events should be to take it apart first to verify exactly what the problem is, then order the parts you know you'll need.

It will save you money on parts you don't need in the long run.

I'm hoping you've done that already.

yeah i took it apart today and it does look like that seall is gone but i noticed something very odd...the bottom bolt that goes the water pump housing and the transmission casing looked like it had a grinder or somthing taken to it it was pretty messed up thhe threads were fine but the shaft of the bolt was pretty messed up any ideas on that?

Probably corrosion from the coolant and/or dissimilar metals eating the bolt shank. Replace it if you think it's bad enough to weaken the bolt..... keeping in mind that is a lightly stressed one.

That shows you why it's important to change your coolant frequently. The aluminum in the engine corrodes and becomes little particles of Aluminum Oxide (The same thing that sandpaper is made out of) So all the internals of your engine are getting basically a sandpaper bath.

Good piont Tech.

Why dont you guys run red dexcool coolant in your engines. GM and most of the engine manufacturers switched to it because of its ability to hepl control corrosion between dissimilar metals and reduce cavitation