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RE: Fuel distribution lines surgery and related matters


As I'd forgotten, but was pointed out, yes remove the bottom two but just
loosen the top two subframe bolts and rotate the subframe up without total
removal. I definitely did not have to do the "hang from rafters" trick just to
get the airbox loose; I'm pretty sure I did it without help. I might have used
a wood block or two to prop things up. I don't even recall disconnecting any
electrical or brake lines.

As others have mentioned, this might be a good opportunity to check the clutch
and lube the transmission input shaft splines (but as Bob Covey warned, that
could end up a wasted effort).

A little history here: for many years K-bikes had a service schedule to
lubricate the splines every 40k miles. When the R1100RS came out, BMW thought
they had solved the metallurgical issue, the splines were intentionally
assembled without lube at the factory, and owners like me were told there was
no service requirement.

I checked mine when it had about 50k miles on it, and both the clutch disc and
transmission input splines were worn out. With later oilheads this service
might not be needed, but with an early RS like yours, if this has not ever
been done and the bike has anything like 40k miles on it, I would definitely
recommend doing it. I don't know if you are comfortable doing that work
yourself of not; I had lots of experience with airhead clutches so I tackled
it myself and had no problems (other than six weeks of downtime most of which
was due to warranty haggling; and it turned to spring in the middle of
February right after I took it apart. Arrrggh!). I would not attempt this job
without experience and a manual, but if you have both I say go for it. On
reassembly I lubed the splines with a very light coat of red lithium grease.

If it turns out there's a problem, you can just put the transmission unit in
your car trunk and set it on the bench at the BMW shop, and have them do the
internal work (many special tools required, not worth doing yourself). That
would at least save you what the shop would charge to do all the external
work, which I assume would be considerable.

Note you'll need an industrial heat gun to separate the rear drive assembly if
you need to do that. Conceivably you could do the clutch inspection and
lubrication with the wheel and rear drive still assembled and attached to the
transmission--unbolt enough stuff so you can just roll the whole assembly back
away from the engine. This would save a TON of work, but the assembly would be
extremely unweildy and you'd risk bending the clutch rod or other damage if
you lost control of it. I wouldn't attempt that without at least one helper,
maybe two, and can't really recommend that approach at all. But it might work
and if it did, would save a LOT of time.

Re: tank vent lines: since gasoline has spilled into the canister, it is now
permanently contaminated, completely clogged, and totally non-functional. It
needs to be removed immediately because it will cause a number of problems if
you don't. You can replace it if you want, but most riders just drop the extra
weight and route both vent lines down behind the transmission so any spillage
in the filler neck is routed directly to the pavement. IIRC you'll need to add
some length to the vent lines to accomplish this.

Good luck!

John Dancoe
'93 R1100RS