Oil leak from rear end

[Jimbolong]

About a month ago I started seeing oil leaking from the rear end of my V7 classic.  Yesterday, I rode about 30 miles (it was very hot - 95).  I stopped for about an hour and then rode back the same 30 miles.  These are pictures of the bike the next morning.  You can see the oil around the breather vent and the oil accumulated on the rear wheel.  Any idea why this is happening and what I can do about it?

[Jimbolong]

Ok, I see my images didn't appear.  I will go read the instructions again and try over.

[Jimbolong]

[rtbickel]

Looks like it might be overfilled and/or a bad o ring or crush washer on the breather

[pehayes]

Slight chance  you have lost the output seal at the transmission and extra oil is draining back to the rear drive.  I would drain both, measure the volume that you drain, and reinstall the same oil plus extra where needed.  If you find the transmission 50cc low and the rear drive 50cc high, you have a hint where it is coming from.

Patrick Hayes
Fremont CA

[rodekyll]

The oil color on the wheel looks wrong -- water contamination?  If water has gotten in there the level has risen and it's overfull.  I'd go with Pehayes' suggestion and add to it to check the color of the drip against the used oil from both boxes.  If it looks like mustard in one and cola in the other there's a water leak.

[Vasco DG]

The smallblock bevelboxes are sealed at the pinion so it won't be oil from the gearbox but the suggestion of overfilling is the most likely. Given the experience of others I would suggest that you drain and measure the amount of oil in both the gearbox and bevelbox as despite their obvious size differences it seems that some 'Technicians' can't work out which type and quantity of lubricant goes in which component. If the Bevelbox is overfilled then the gearbox is likely grossly under filled and will by now of suffered substantial damage. This may not be the case but it is certainly worth checking.

If you have washed it recently with a hose or pressure washer or have ridden in heavy rain water may also of got in via the breather.

[Jimbolong]

The oil level was definitely too high and I'm pretty sure it had water in it.  I drained it out and refilled to the proper level.  We have definitely had a ton of rain here over the last month and much of the time the bike was out without a cover.  I hope that was the problem.  I just ordered a new breather and gasket just in case there was anything wrong with them.  Thank's everyone for your help.

[Vasco DG]

Jim, check your gearbox oil level too. Take the filler plug out of the RH side of the case above the brake master cylinder and hold the bike vertical. Now tip it ever so slightly to the right. Oil should begin to dribble out. If it doesn't then the gearbos is under filled. If it has only had 185ml added after draining, (Seemingly a rather common occurrence, I have no idea why?) then the box may be seriously damaged.

Pete

[twhitaker]

If water is getting in through the breather you might consider installing a 'remote breather' up under the seat.

[SED]

When mine did this it was due to gear lube from the transmission migrating back to the rear drive because both seals were bad.  [edit] This was a 30 year old Monza - not a new bike, so not surprising that two seals were weeping.

Also, if the swing arm boot is torn you could get water into the swingarm pretty easily.  If it then leaks past pinion seal could cause the same problem.  A torn boot seems more likely than water through the breather.

Let us know what you find.
Shawn

[Tom]

Hope you found the problem with water migrating into the rear end.  You might have to drain the oil again allow time for the water to completely drain out.