Mystery oil leak?

[The Grey One]

The last time I rode the bike I was alarmed to see oil on the rear wheel. Even more so as I was at the top of the Mangart road in Slovenia. It looked like the final drive oil seal had failed. I cleaned most of it of the rim and then wobbled back down this narrow and unforgiving road thinking that I could pillion back to base to collect car and trailer. When we stopped at the bottom there was no sign of a leak. I don't think it could have all already leaked out as there was only a small amount on the rim when I first noticed it.

The history to this is that I had experienced clutch slip and asked on here about this. One suggestion was possible driveshaft problems. So I had stripped the bike down, marked the shaft, refitted and road tested, stripped it again to see that the shaft was OK and put it back together again. The last time I had it apart the final drive tipped over on the workshop floor and spilled oil out of the ABS sensor hole. When I put it back together I filled it with fresh oil.

The bike is now stripped down for a new clutch.the plate is oil soaked, but the final drive seal looks perfect and there was no perceptible play in the bearing.

My question is could there be some way some stray oil could have been trapped when the final drive was on it's side? I had ridden for around 2 hours before the stop at the top of the Mangart. The amount of oil leaked was small and no further leak showed on the (cautious) ride home. The level looked fine when I got back but we are talking about maybe a few cc's of oil on the rim. I will probably fit a new seal anyway but I still feel mystified about this.

John

 

[Steptoe]

Common and nothing to worry about.
The final drive input shaft can breath, usually after a long ride, more so in very hot weather.
Had a few bikes show the symptom when doing the moroccan dash, 1400 miles in two days, 4600 miles over 8 days.
Even new seals can do it.

Check the final drive level just to make sure, but you'll find a little oil goes a long way.

 

[The Grey One]

Common and nothing to worry about.
The final drive input shaft can breath, usually after a long ride, more so in very hot weather.
Had a few bikes show the symptom when doing the moroccan dash, 1400 miles in two days, 4600 miles over 8 days.
Even new seals can do it.

Check the final drive level just to make sure, but you'll find a little oil goes a long way.

Thanks for that. I was just a bit concerned, it has never happened before and although there was not much oil it was finding it's way onto the rear tyre-not what you want at the top of an alpine road!

I have to wait now until next spring to ride the bike again. In Austria we hand in our number plates for the winter-saves on tax-and my bike is sealed away in the bike garage.

John