BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

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R1150R, 2002. 35k miles.
Oil is leaking from underneath the rear swingarm (paralever?) at the point where there's a rubber gaiter/bellows/sleeve thing which connects the swingarm to the bevel drive housing at the back.
The rubber bit appears to be held in place with cable/zip ties?
Is this normal? Will it be expensive to fix or should I just ignore it?

Any advice would be much appreciated.

Oil is leaking from ... rubber gaiter/bellows/sleeve

How much? Weep (resulting in dirty grimy area), drip (sometimes seen on rear wheel when bike's on sidestand), or puddle?

The source is transmission rear seal and/or final drive.

Resolution is either (1) keep fluid levels up and monitor changes; (2) replace seal(s); or (3) rebuild associated unit.

When similar leak was noticed during 24k service and inspection at dealer for our former R1150R Roadster, the technician's comment included "most of the oilheads do that, it's usually not serious"... and that's response from an experienced guy with trusted opinion.

Search here for more info from other owners.

It's a weep not a drip.

Is it the gear oil in the bevel box, or is it coming from the engine end and seeping down the shaft?

Have contacted my favourite police bike mechanic. Hopefully he can sort it with me having to remortgage the house or sell a child.

b12bandit wrote:It's a weep not a drip.

Is it the gear oil in the bevel box, or is it coming from the engine end and seeping down the shaft?

Have contacted my favourite police bike mechanic. Hopefully he can sort it with me having to remortgage the house or sell a child.

Some people have claimed that synthetic oil in the rear drive can result in a leak, Valvoline semisyn 80-90 does not leak, neither does Redline HD shockproof tranmission oil. Maybe do a FD oil change first? If you use Redline you will know were the leak is coming from (Redline is red).

It could be coming from the transmission and running down. But, most likely it is coming from the final drive.

The most likely cause is that the final drive was filled with a little too much oil at the last change.

As said - if it's a weep then it's not too much to worry about.

Both seals that interact with the drive shaft (gearbox output & final drive input) are (IIRC) above the actual oil level, so they only really get "splashed" when the bike is running. The weep is more than likely less than 10cc in 1000 miles, so it's in the "live with it" range of issues.


I'm pretty sure my bikes been doing it for the last 70,000 miles, I never notice the oil level to be at all low when I check them though.

Mine, and some others did this for a little while, then stopped on its own. I suspect a bit of dirt got caught under the lip of the pinion seal and caused a breach allowing the gear lube to weep past until it got flushed clean. That lasted about two weeks.

They all do that.


well, most of them anyway

The key here is to monitor it closely. Watch the bottom of the rubber boot closely as the oil tends to cause the bottom of the boot to deteriorate. Mine is doing the same thing and my mechanic 30 years experience says 60 percent of the motorcycles that he replaces the paralever bearings on have a similar problems.

Noted guys. Thanks for your collective wisdom.
Having cleaned up the back end I've been monitoring it carefully over the last few days and it appears to have stopped. Will keep an eye on the bevel box oil level. Fingers crossed.