How is water getting in the crankcase on 1989 650 stand up?
also how do you get it out?

 

You have a water drain valve if a block off plate isn't already installed that could let water in if the seal is bad. There would have to be a fair amount of water in your engine compartment. The unit is below the starter. As far as getting the water out you can remove the spark plugs and crank the engine over with your fingertips in the holes or invert the ski and let the water drain. After the water is out I would spray some WD40 into the spark plug holes. If you don't already have a block off plate installed get one.

 

Thank you.
Is the block plate an aftermarket thing, and what does it do??

 

Yes. You can find them on ebay pretty cheap. The water drain valve has a habit of failure which can cause the problem you have but also if not seated properly can cause piston seizure due to a lean fuel/air mixture.

 

Sorry. You asked what it does. It's supposed to drain water that has enters your engine by pulling up on the **** that's at the end of the cable which operates the valve. After a while the unit will not seal properly.

 

I didn't read your post properly. The block off plate covers the sealing surfaces after you remove the water drain valve.