Final Drive leak

[racurley]

Went for a 120 mile this afternoon. Everything seemed good during the ride. When I got home and was putting the bike up sometime later, I noticed oil rear wheel on the FD side. Mostly on the wheel but some on the tire sidewall. I opened up the FD fill plug and it looked low. I topped off the oil but didn't do a good job of tracking the quantity. Maybe 100 ML. There seemed to be some oil around the drain plug but it appeared to be snug.

I changed the FD oil maybe 500 miles ago when I bought the bike. There's roughly 44k on it. I used Mobil1 75W/90 synthetic.

Ideas?

[towerworker]

Might be worth your while to drain the FD and closely examine the drain plug. There is a small magnet imbedded in the center of the plug. A little smooth sludge around the magnet is common but if you see some more substantial stuff then that may be cause for more concern. Possibly the seal itself is failing and no bearing damage. Also check for play in the final drive:

Check the rear wheel for bearing looseness - put the bike on the centre stand and hold the rear wheel at 12 + 6 firmly - wiggle it for detecting ANY looseness. Do the same holding the wheel at the rear and the sub frame, as this also checks wheel and pivot bearings as well. You should have NO looseness.

FWIW--I am aware of far too many stories of FD failure on R's. I did some research many years ago and found this product to be of considerable value. https://guarddogmoly.com/product/gd-401 ... gear-oils/

I've been running it for 60K now on my '04 R and (so far) have 0 (zero) FD issues. I put it in the tranny as well. Good luck with yours!!

[Biff's R]

I have stuck with the 80-90 dino oil in the transmission and FD. I just remember reading a long time ago about sticking with the dino in those weights .

[Buckster]

I still use synthetic in the tranny but went back to dino in the FD. I also use the Guard Dog moly in both.

[sjbmw]

What tower said. Get that plug out and look for any metal. Had the same issue a few years ago after a day long ride home from the Hungry Mother bash. Drops of oil on the rear wheel, but check the underside of the shaft, and see if the oil is coming from the front boot and running down the shaft.

Mine was the front bearing, not the rear bearing. Paul Glaves wrote a MCN article about improperly shimmed front bearings at the factory, and that was exactly my problem.

I got it replaced and re-shimmed correctly just in time.

[racurley]

Ok. Will check this out when I get back in town.

If I were to need a seal or a bearing, where do you source these parts?

[racurley]

So, changed my FD oil tonight. Some small metal flakes. However, perhaps more telling were the chunks of rubber. I'm guessing this is evidence the bearing is going?

Any recommendations on where to obtain a new bearing and seal?