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Hi guys. My 1983 R80RT is leaking oil through the ground screw that holds the speedo cable to the transmission. At first I thought it was the drive shaft boot leaking but after a long ride yesterday I saw it was coming from that screw which is also supposed to vent the tranny. What should I be looking for here? This is my first airhead and still getting the hint of it.

The gearbox could be overfilled, or it could be swingarm oil migrating past the forward seal.

I would start with a gearbox fluid change, but it is only filled to the bottom of the fill plug threads, so it would be hard to overfill it a lot.

Probably the swingarm. That is the lube for the U joint. Worth checking out.

I would open the fill plug and see if any runs out, with bike on the center stand. It holds 800cc.

I had one of these oil cans to fill my gearbox. I think at one time I counted the number of pumps to get the 800cc. That was a long time ago. It works for the gearbox, driveshaft housing, and final drive.

https://www.amazon.com/GOLDENROD-707-In ... P75PTBJ1W7

If you haven't done it yet, I would be inclined to change the transmission oil without delay. It probably needs it anyway but one of the causes of blowing from the vent is water in the oil. As the engine and transmission gets hot, the water will evaporate presurising the box and causing venting which carries oil with it. As has been said, it's a good idea to make sure you've got the right level of oil as too much oil will cause leakage. You'll also want to change the drive shaft oil and final drive oil while you're at it. As you drain the fluids, check for shavings and filings in the oil that comes out... that is a sure sign of problems to come...

Rob

I read on Snowbjrn site about this. I took out the screw and cleaned it through. There was a bit of debris in there. Took her out for a 2 hour ride and when I got home it didn't leak one drop. Next Sunday I'm taking her out for the Distinguished Gentleman's Ride. Let's see how it goes.

PAS wrote: ↑Sun May 16, 2021 1:25 pm I would open the fill plug and see if any runs out, with bike on the center stand. It holds 800cc.

I did and yes, some oil ran out.

If you have not done a complete fluid change since buying the bike, it needs to be done before next Sunday. The gearbox, anyway. It's the gentleman thing to do.

That's the first thing I did when I bought the bike along with new brake pads, battery and the oil and air filters.

So if the speedometer cable that attaches to the rear of the trans has not been sealed, water can get into the trans. Does the trans oil look milky?