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1973 r60/5

v-man

New member
I recently bought a 1973 R60/5 Hack. It is in very good condition but has a few issues I willbe dealing with. The most important are the oil leaks ... slight leaks from left side pushrod tubes but more importantly (see picture below) I have a leak from just above the oil pan in rear of case. The hole is perfectly round and smoothe, no threads. I have talked to BMW dealer and we looked at a /5 he had and there is NO HOLE. I have a buddy in MD with a R75 that has same hole with a grey plug in it! I'm not sure what the hole is here for OR why some have the hole and some do not. I was planning on dropping the pan during cleanup and thought maybe I'll just tap it and thread a bolt into the hole ...

Anybody know why this hole exists? What's it for and why do some have and others do not have it?

Thanks for any help, I'm sure I'll be asking plenty of questions in near future!

Don

1973_R60_5_weep_hole.jpg
 
That is a weep hole. If oil comes out of there, it is really coming from the rear main seal or the oil pump O-ring, or both. Or, if it smells like gear lube, it might be the transmission input shaft seal. The motor casting forms a sort of shelf right under the transmission. If you were to put a plug in it, the recess of the shelf would eventually fill with whatever oil is accumulating there and then over flow just the same. If you can get low enough to take that picture, you can easily put a finger on the surface above and inboard from that hole. You'll find an accumulation of oily gunk residing there.
 
+1 on what James said.

My '73 R75/5 has the hole.

It would eventually fill with oil, but rain water would be more likely to fill it sooner.
 
Did only the /5s have this hole? I've never seen anything like this on an Airhead. Isn't that a hole into the sump? I know about the hole in the bell housing that will drain the clutch area, but that drains to the shelf out of which there isn't a hole or path...it just collects there until spilled, wiped out, etc. The shelf is the top part of the engine casting and the top part of the sump.

This looks like a PO mod to me...correct me if I'm wrong!!
 
+1 I am with 20774 - if the rear main seal or oil pump cover is leaking, the (engine) oil will come out of the bell housing/transmission interface seam and end up on the top shelf just above that hole. That hole appears to go into the sump, and why someone would put that there I dont know - I haven not seen a hole like that on either of my 2 airheads or on numerous others that I have looked at... maybe I do not get around enough...
 
The /5's casting had that hole (the hole in question is not threaded, nor is it supposed to be plugged, and it does not go into the sump.), the /6's and later had a spacer tube and a large gap underneath, as shown:

20100310008.jpg


As a side-note, these are the two suspect areas for the oil leaking from that hole; the rear main seal and oil pump o-ring.. unless it's the transmission leaking.

Also, unfortunately, the BMW dealers I have dealt with have been virtually useless in terms of helping me with my airheads. We have to teach ourselves about our bikes these days. Oh, just have James.A teach us (that's what I did!).
 
Thanks everybody ... it's so odd that some have seen the hole and know about it and others not. I spoke with somebody at MAX BMW and instantly he knew about the hole and it seems either the rear main or oil pump seal or BOTH are bad. The leak is definantly engine oil and not gear oil ... gear oil would mean a transmission output shaft leak.

While bike is apart is there anything else you guys would suggest looking at or replacing? I'm thinking maybe replace clutch while it's all opened? Maybe still do the output shaft seal?

Thanks for all your thoughts and any advice you might have!
 
While bike is apart is there anything else you guys would suggest looking at or replacing? I'm thinking maybe replace clutch while it's all opened? Maybe still do the output shaft seal?

Thanks for all your thoughts and any advice you might have!

Before you start to open up the back end of the motor, (crazydrummerdude's picture) be sure to block the crank at the front of the motor. I usually tape together a stack of quarters (maybe a $1.50's worth or so) and then tape them to the front of the alternator rotor and then re-install the front cover. You want a small gap on the front cover to the timing cover when the bolts tighten up. This is VERY IMPORTANT.
 
You gots better eyes than I does Hawkeye. From that image I couldn't tell you if it did, or did not, have the hole.:lurk
 
I think the difference is that on the blocks without the hole, the engine mount bolt runs through the space tube and the diameter of the tube leaves a little gap to the shelf....this is where it can drain. If someone has a picture of the earlier ones, I suspect that there is no gap with the bolt tube, thus requiring a hole.
 
You are exactly correct. No hole on the 1974 R90/6 because there is a gap between the bottom of the round spacer and the block.

Barron
 
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