Annoying Oil Leak

[vontresc]

Well It's time for the annual heavy maintenance on the ol beemer. My goal for the year is to finally fix that annoying oil leak on my 81 R65. Before I start tearing things apart, I'd like to get some opinions on where the cause may lie.

Ok so here are the symptoms.
When I put the bike on the sidestand I notice a little puddle of oil on the  left side below the bike. It looks like the oil is coming from the "shelf" below the tranny, and running down by the oil fill plug. I am pretty sure it isn't the oil fill plug. this leads me to believe that it may be the rear main seal, or the oil pump  o-ring. The worst part of this is that I put in a new friction plate last year, and didn't really look at those places :-(.

Are there any other sources I should look at while I am doing major exploratory surgery??

thanks

Pete

P.S. Yes I know that I will need to block the cam if I remove the flywheel completely

[Bob_Roller]

Your descripton of the area of the leak would lead me to believe that it either is the rear main seal or the oil pump cover seal.

By chance, did you recently change your oil to a full synthetic ?

I did this ( Mobil 1 motorcycle oil), and about 3-4 months later the rear seal started leaking, went back to Spectro Golden oil and it stopped.

[trolle]

I agree with Bob but recently I had a leak giving the same "symptoms". I suspected the main seal as well but found out, that the vent hose from the crankcase ventilation had cracked leading the oil from the top of the engine down the along the crack between the engine and the transmission in such a way that it looked as if it came from the shelf under the transmission. Much easier to repair or change than the main seal!

greetings from a sunny but cold north with good riding conditions

trolle

[vontresc]

Hmm good through Trolle. I'll have to check that first to see if that's the problem. I'll also have to look at the old clutch disk again. I don't seem to recall there being any oil on it, and I remember hearing that a main seal would cause there to be oil on the clutch.

Hmm sounds like Denmark has better WX than Wisconsin. We broke 100" of snow this year, with 2-3" forecast for tomorrow :-(

Pete

[Bob_Roller]

If by chance you do need a crankcase breather hose, post here first, as it's a little difficult to find in the parts catalog.

It was 88 F. here in the northern Sonoran desert of Arizona yesterday, currently about 70 F. at 9:30 am.

[vontresc]

Actually I will take you up on your offer for info on the breather hose. It may be the source of my frustration.  The swan neck hose on top of the breather valve is cracked at the base, and there is a fair amount of oil grime on top of the case be the starter. Well at least I got the swingarm, and driveshaft off tonight. Only took me 90 minutes.

Pete

[Bob_Roller]

The part number is : 11151335735, just to confirm what the hose looks like, after it comes off of the breather valve housing, it makes a 180 degree turn, then a 90 turn, has a short straight run, then flares out to a larger diameter with two ridges molded into it, to snap into the airbox.

Price is around $30 plus tax and shipping.

[Joan]

Is it MOTOR oil or GEAR oil?

Used gear/transmission oil smells awful, imnsho. Blarg!  

[vontresc]

Ok folks I need some advice here, I got the transmission out, and the flywheel removed. So now I am looking at the crank, and all the pictures in the Clymers manual show what looks like some sort of soft seal. Instead I see a metal ring, and What I am assuming is a cap over the crankshaft (see pic attached). The manual now tells me to "remove old seal". I'd like to try, but I don't see one. I assume I still need to remove some more parts, but I didn't want to munge anything up so I stopped for the night.

Any suggestions would really be appreciated.

Thanks

Pete

P.S. sorry for the poor quality of the pic. All I had was my cell phone

[nhmaf]

What model year is your R65 ?  I believe that BMW has a different type/style seal for the pre- 85 models that had a thin, tapered edge for sealing.
From 85-on, they used a soft/ pliable material called PTFE that was more elastic, sorta like the fork slider seals.   It is important, before you go further,
that you have the proper type of seal in hand.  Maybe the newer, post '85 seals will actually work on all bikes, I do not know myself but I bet someone here does.

They (BMW) also wants you to be sure to check the depth of the existing seal before removing it, so that you can put the new seal in to the same depth.
you don't want the new seal to rub against the flywheel (pre-81 models) or the flywheel mounting ring (81 and after)


P.S.  If you have the "old" thick black Clymer manual, look in Chapter 5, Page 203, illustration #10 - does this look familiar ?

[Justin B.]

Pete, please tell me that you DID block the crankshaft to prevent it moving forward...

[MrRiden]

I haven't been where you are yet but a check of the parts fiche indicates that you are looking at the Guide Ring [11 22 1 337 248] when removed [how?] will reveal the gasket ring [11 22 1 337 099] and the shaft seal [11 11 1 338 342] living behind it. The diagrams on reaoem are pretty clear and I'm sure someone with actual practice will chime in.
rich

[vontresc]

YES I blocked the Crank, and i have been VERY careful in not applying a lot of forward pressure on the crank.

This is a 12/81 (so almost '82) model, and I looked at the fiche, and it shows a guide ring. I just don't know how to remove the thing. Anyway I am heading to the local BMW dealer for parts tomorrow, and maybe I can get some info there.

Pete

[trolle]

Changing the rear main seal: see http:// http://picasaweb.google.dk/petertrolle/BmwR6584Restoring/photo#5183125971925896002  which is a drawing I made after having installed the seal the wrong way twice (yes I know that this sounds stupid!)

The new seals have a soft lip as you can see from the drawing, this lip must rest on the crankshaft cup as shown in the drawing or else the engine will blow oil out faster than you can imagine!

To remove the seal use a screwdriver and a plier and be very careful not to touch the engine casing at any point - even small scratches at the wrong place will allow oil to get past the seal. You cannot remove the seal without destroying it!

Let the new seal soak in engine oil for a couple of hours before you install it.

Remove the crankshaft cup (see drawing) before installing the seal to ensure that the lip of the seal points inwards.

IMPORTANT Place an empty paintcan between the seal and the wooden board you apply your hammer on when you tap the seal into place, the circumference of  a 1 litre or 1/4 gallon can matches the seal. The reason for this is that the seal must rest evenly in the seat to be tight.

When you are at it, change the O-ring of the crank shaft cup  as well.

Have a nice time.

greetings from a grey and windy north waiting for spring. Deplorable driving conditions

trolle

[nhmaf]

you have some very good photos on your website, trolle !

I knew that I had seen some good pictures of the rear main seal installation, and finally found some, with instructions/advice, on
snowbum's website.   I'd recommend that people go here to read the advice and observe the photos to help with the installation
and removal of the guide ring.   I know that some people have installed rear main seals without use of one of the BMW special tools, or
one of Ed Korn's special tools - this might be a case where having such a specialized tool may be worth it though, to increase one's
chances of success the first time around.  I haven't had to replace my seal yet, but I've been watching it and keeping my fingers crossed !

Here is the link to snowbum's article and pictures.  It sounds like the guide ring removal (he explains the removal process in words only, no
photos of that part unfortunately) process isn't too bad, but is a bit "fussy" - be very careful not to ding up anything or the ability of the seal to work properly can be compromised.

http://bmwmotorcycletech.info/flywheelremovalwarning.htm