Airhead Engine/Tranny seal exploded and oil spilling...!

[Rohls]

I have a pretty big problem. In short, a friend and i are on a 4000 mile mototrip around the west coast of the USA. Me on my 1975 R90/6 and him on another bike. For 3300 miles everything was fine, until somewhere along the Idaho/WA interstate my bike decided to spill its entire oil contents on the freeway whilst going 70 mph.

I believe the seal between the engine and the transmission (output shaft or spline shaft seal?) has broke.

The clutch is sticky, but functional. The oil that is spilling is definitely engine, and not tranny.

The bike was towed to Seattle, WA via my great friends whom I am so lucky to have.

I have to get back to California in a couple of days and would love to fix my bike.

Would a reasonably mechanically inclined person like myself along with a small garage with basic tools be able to fix this?

What is the name of this seal?

What are the basic actions that need to been performed? (Tranny removal, any pullers needed?...)

Anyone have a link to a micro-fiche ( I check bike bandit and bobs to no avail...)

Bike shops are closed today...

Please help !

Thanks!

Nick

[gspd]

Sounds like you blew out your rear main seal.
You'll need some long bolts and nuts to remove and install the clutch, might need a new clutch too.
No other special tools are absolutely required but a main seal installing tool makes it easier.

[pkboxer]

11 11 1 261 739 rear main seal 80 x 100 x 10 1970 on $ 22.00

To do this and get home, you should just need this, and the clutch removing bolts.

These are 3 bolts the same as the clutch mounting bolts, but longer. And matching nuts, used to slowly back off the spring pressure.

You also need to block the crank, as described here....

http://bmwmotorcycletech.info/flywheelr ... arning.htm

In a pinch you can reuse the bolts, even the flywheel and driveshaft bolts. But if you can get em, might as well replace them.

You can install the seal w/o the tool too.

I'd think this can be done in 3-4 hours or so, even if it's your first time.

Here's a link to an article for this....

http://www.ibmwr.org/r-tech/airheads/rtrany.shtml

[wirewrkr]

This is one of the better microfiches available, the prices are updated every time BMW raises them, and the fiches are mostly accurate.

http://www.maxbmwmotorcycles.com/fiche/ ... d=03192010
Better than real oem, and bike bandit.
The current correct number for the factory main seal is 11111338342, the current m.s.r.p. is $25.60.
I don't recommend oiling the lip, some do but most don't. factory school said "don't". I DO however recommend form the seal lip slightly so as not to scar as it slides over the end of the crank. It's not rubber, it's teflon on the sealing area.
you will need an oil pump o-ring (that may be all that is wrong) 11411335895 $3.69
Also some later /6 bikes had an o-ring in the flywheel itself, 11221337099 $3.69
Don't forget DRIVESHAFT BOLTS! 26111242297 (x4) $1.60 each
these are the newer style with no washers needed. I recommend them for all airhead applications.

[Garnet]

Is it possible for the oil pump O ring to suddenly fail giveing the same results?

[gspd]

Is it possible for the oil pump O ring to suddenly fail giveing the same results?

It's very possible, but I've never seen one suddenly let all the oil blow out.
I'd replace it either way.
There's going to be oil all over the place in there so it will be hard to determine where the leak started unless the rear main seal or oil pump o ring are obviously blown out or damaged.

[Deleted User 287]

Do you know when the last time the input splines on the transmission were serviced?
If not, you should clean them, as well as the mating splines on the clutch.
Relube the input splines only, along with a small dab on the tip of the clutch throw-out rod.

Honda Moly 60 might be the easiest to find (most Honda m/c dealers have it), although Wurth SIG 3000 is supposed to be good, too.
Any grease with a high molybdenum content should work.

[wirewrkr]

the o-ring rarely fails, but the pump covers mange to loosen up.
That is what I have observed over the years, doesn't matter, if your in there, you should always change it.

[Jean]

A 3" PVC coupling from a big-box store (LOWES, HD etc) makes a great seal installing tool. Be sure to notice how deep the original seal is recessed, or if it is flush, AND BE SURE TO NOTE THE DIRECTION OF THE LIP when you install the new seal!!
I really hate to say it, but it sounds like some foreign object caused this sudden loss of oil. Check ALL the other possible locations around your engine for possible leakage locations...push-rod tubes for instance.

[ME 109]

Is there a gallery plug on the back of the engine on a /6?
Ida thought the oil pump cover would give an initial slow obvious leak whether the o ring failed or the bolts loosened off.