So my ‘85 RS is fully disassembled and I wanted to save some time cleaning the gearbox. I used a pressure washer and only now understand why that’s such a bad idea, especially for the gearbox.
There’s a pretty high chance that I got water in there. I still haven’t drained the fluid in there (old fluid sitting since at least 2013). 
What’s the best way to proceed?
I was thinking of draining it tomorrow and checking for water, but what do I do if I find water??

The water will go to the bottom because oil floats so hold it in the normal position and drain the contents then fill with fresh oil.

After you drain the water and refill with fresh gear lube, it would be a good idea to take the bike for a good run and check the oil.  If it looks milky, you need to do another drain and refill.

clappy wrote:So my ‘85 RS is fully disassembled and I wanted to save some time cleaning the gearbox. I used a pressure washer and only now understand why that’s such a bad idea, especially for the gearbox.
There’s a pretty high chance that I got water in there. I still haven’t drained the fluid in there (old fluid sitting since at least 2013). 
What’s the best way to proceed?
I was thinking of draining it tomorrow and checking for water, but what do I do if I find water??

I guess it all depends how close you got with the pressure washer…and at what level of disassembly you had the gearbox at the time. If you have gone up close and personal in the vicinity of any of the seals, you probably will have got some water inside. I would follow Rick G & Point-Seven-5’s advice - drain down the gearbox and visually check the condition of the oil. If you’ve got a suitable clear container, decant the oil into that and let it stand for a few days to see if water separates out. If your pressure washing antics were done with the gear box off the bike, then it is likely that the oil will not have emulsified (i.e. hasn’t had the mechanical churning and gear meshing that causes the oil and water to mix together into a cloudy emulsion) and any water may have simply sunk to the bottom as Rick says. If the oil has been there since 2013, however, there is a good chance it might be cloudy/milky anyway, without your recent efforts. If you do find the oil is cloudy/milky/emulsified…I would fill and drain the gear box with fresh oil to help flush out any water/contaminants and then re-fill with fresh oil.

On an assembled bike, I keep at least 2’ away with the pressure washer and avoid fragile areas like the radiator (I have attributed at least 2 (aging) radiator leaks to my over zealous use of a pressure washer).

clappy wrote:I used a pressure washer and only now understand why that’s such a bad idea, especially for the gearbox.

Actually, pressure washing is especially bad for the multitude of electronics in this moto because it can interrupt circuits and create an environment for oxidation. Your gearbox isn't a problem. Like BAE indicates, any infiltration into it by washing or condensation can simply be drained off and replaced by fluid. You are aren't going anywhere, anyhow right now anyway.

Get a good cleaner that will do a good job of cleaning with light scrubbing.  Never use water pressure to remove grease from engine or drive train components. 

If necessary, disassemble the bike around the area you want to clean so you can get at it with a brush or a sponge.  Work the cleaner a bit and rinse with a gentle spray. 

I have found that S100 is an excellent cleaner that will remove dirt right down to the finish with light scrubbing.  It's one of the favorite cleaners among Harley riders, and we all know they are the most anal compulsive motorcycle detailers and polishers.

I would drain the box and use PARAFIN to flush out any water or crud. Personally i use a MOLYSLIP oil mix gives smoother gear changes

Thanks all!