The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: personman on August 08, 2015, 07:31:27 PM
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Hi guys. Proud new owner of a 1981 r65 here. Lots to learn. Lately I'm observing a pretty heavy oil leak coming from what I think is part of the gearshift mechanism. One of the photos linked below is of the leak itself and the other is of the site of the leak in context. It's bad enough that I can watch it leaking, and I also get a pretty good puddle under the bike where I leave it in the garage. The leak seems to gotten a lot worse after the engine overheated while idling in traffic on a 102 degree day for a long period of time, so I think that the high heat might've damaged the seal there, but I'm not sure. Definitely learned my lesson either way not to let it sit in traffic with the engine idling.
Should I order a new oil seal? What would be the name of the part id need to buy? Other thoughts and unsolicited advice are most welcome as well.
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Go to your friendly local bearing and seal place and buy a 26x7x16 seal.
However, if you do not know how to remove the old seal (and put a new one in for that matter) stop at this point unless you have a knowledgeable friend who knows how and can show you.
It's not hard, in fact you will probably be OK if you follow Snowbum's essay on the topic (bonus points if you can stay awake to the end bye-the-way). There is a bush in there, I've never had to change one, but while the seal is out you should test the bush for movement - putting a new seal in after a worn bush will mean that you waste the couple of dollars for the seal and 30 minutes of your time.
Oh, and one last thing, after removing the fuel tank (and your battery if it is not a fully sealed or Gel type) lay the bike on the RHS with the rocker resting on a lump of 4*4 with an old sock on top of it - otherwsie you are going to lose about 300cc of smelly 90 weight oil when you pull the shifter shaft. on the other hand, this might be a good time to give your bike a "getting to know you" gearbox, shaft and final drive oil change (you need 2 litres of EP hypoid oil and a thing called a "sludge pump."
Sorry, a second last thing - before you pull the drain bolts on the gearbox, shaft and final drive, try loosening the filler bolts first....Just saying cause it is a crapload easier to solve problems on the filler side before you drain all the oil out.
1981 R65 you say? Interesting that it has the earlier "bent coathanger" shift link (I think they changed 1980 year model but someone will correct me if I am wrong on this).
Overheating your engine is incapable of transferring enough heat to the gearbox to do it any harm - I suspect your leak is more to do with the learning process your left foot is going through getting used to airhead gearbox idiosyncrasies.
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Like Tony said, engine temps won't get enough heat to that seal to cook it (and you'd be riding a boat anchor if they did). Ambient temps and warming the gearbox up by riding will warm up and thin out the gearbox oil, making it leak more easily. Makes the puddle on the floor look bigger too.
If you overheated the engine I'd consider a motor oil change, as oil does get broken down when the temps get too high.
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Thanks guys, that's really helpful. I don't have a friend/mentor to help me change the seal. Hopefully the essay luca referenced will be a good guide.
Interesting about the heat. I just started to notice the leak on the day of the overheat, so it makes sense that the high ambient temp (Houston, July) could have just thinned the oil so it flowed out faster. And I probably will do the full oil change -- about that tim, and a good way for me to get friendlier with the bike
I'm getting pretty familiar with the shifting idiosyncrasies, but what did you mean exactly about the left foot? Curious so I can adjust/correct.
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Here's a link to a parts catalog .
http://www.realoem.com/bmw/enUS/showparts?id=0364-USA-09-1980-248-BMW-R65&diagId=23_0256
The seal you need, is number 9 .
If you don't have an airhead friendly dealer near you, the dimensions of the seal are on the description of the seal .
You should be able to source a seal other than a dealer .
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Note the depth of the old seal prior to removing it. Seat the new seal same. Use a socket-to-fit and tap it in square. Little bit atta time does the trick.
After removing the bolt, you'll pull out a length of shifter shaft. Don't be alarmed, it's what it is.