1977 R100RS, recent acquisition. I ran the motor for a few minutes to check the motor oil, checked the final drive and gear oil while I was at it. The gear oil level was good, but the oil was foamy. I'm guessing there is water in the oil and that I can probably fix that by changing the oil (maybe more than once?) . What concerns me most is that the bike hadn't been put into gear, so I don't see what would cause the oil to foam like that. Any help is much appreciated!!
Water in oil usually shows up as thick green slime, like someone smushed a lot of caterpillars or some such. It is usually the result of washing with a high pressure hose. In those cases, the oil should be changed. Getting the oil up to operating temp will "cook-off" the small amount of remaining water.
I can't help you with the foam except to suggest that you may have pushed your bike around in the garage just before making the inspection.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
The bike hadn't been moved since the day before. I changed the oil, so we'll see how that goes. Thanks for the feedback!
Usually, water in the gearbox is due to a perished speedometer cable boot. If it's hard and/or cracked, water will get into the trans. Replace that boot. I also add a small zip-tie to snug it further. But this is a common problem. a $0.50 rubber boot can destroy a $1500 gearbox.
Antny
If you had the clutch out while it is running in neutral the input shaft is spinning in the trans.
Ah! That makes sense! Thank you!!!
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