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Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Mon Feb 22, 2016 11:18 pm
by lskbike
I started removing the transmission from my 1989 R100RT this evening. As is required, I removed the bolt that secures the speedometer cable into the transmission and also secures the battery's negative cable to ground, (the transmission). After removing and inspecting this bolt, I noticed that it is solid and not drilled thru, as I have commonly seen in older BMW's. It is my understanding that the "hole" in this bolt is necessary in all airheads so that the transmission can vent to air. I also was under the impression that if the transmission isn't properly vented it can damage the seals, which mine are leaking on this low milage bike. I am wondering if a previous owner may have lost the factory "vented" bolt and not knowing any better, replaced it with a "solid" bolt. Can those of you that are knowledgable in regard to this, please advise if this bolt in an 89 R100RT should be vented (drilled), or not... AND if it isn't supposed to be "vented" thru this bolt, when did BMW change this and how does the transmission "vent" in this case?
I appreciate any help you experts can provide...Thanks....
LSKBike
Southeastern Indiana
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Tue Feb 23, 2016 12:10 am
by SteveD
The gearboxes didn't change much. The circlip was missing around '89 but that bolt should be vented still.
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Tue Feb 23, 2016 5:45 am
by PAS
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Tue Feb 23, 2016 6:50 am
by Rob
Yes, you want a vented bolt.
This is not the first time this question has come up. The answer will always be the same.
POs. Can't live with them, can't live without them.
edit: lskbike, check your personal messages
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Wed Feb 24, 2016 7:56 pm
by lskbike
Thanks Guys...explains why gear lube is has been dripping out the back opening of the transmission where the clutch operating lever is...dripping down the lever onto the exhaust system then baked on... Non Vented/Pressurized transmission is never a good thing...
Rob...your right Prior Owners! Can't live with them, can't live without them... funny how they apparently didn't notice the leak or... it had to at least smell like burning petroleum product...
LSKBike
Southeastern Indiana
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Thu Feb 25, 2016 1:09 am
by ME 109
lskbike wrote:Thanks Guys...explains why gear lube is has been dripping out the back opening of the transmission where the clutch operating lever is...
Maybe.
Maybe the boot has a hole in it.
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Thu Feb 25, 2016 8:01 am
by PAS
Where did my picture go?
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Thu Feb 25, 2016 8:48 am
by SteveD
PAS wrote:Where did my picture go?
Here it is! Best check your link...
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Thu Feb 25, 2016 9:16 am
by Rob
Motobins will let you link to their images (so will Huckys, but this is a better picture)
23 11 1 230 599
BTW - Motobins does not ship to the US.
Re: Transmission Bolt in a 1989 R100RT without Vent Hole
Posted: Thu Feb 25, 2016 9:17 am
by Rob
SteveD wrote:PAS wrote:Where did my picture go?
Here it is! Best check your link...
I can't see that one, either, SteveD.