oil on clutch

[41107]

oil is comming up the pushrod thru the center of the transmission input shaft messing up the clutch. 1998 r 1100 rt . should there be any kind of a seal,o-ring something,around this rod to keep the oil away? i don't seem to realy see anything in maxes parts fiche.

[Andy VH]

Hmm,...lemme see if I'm reading this right. The only pushrod "tube" at the center of the clutch is the clutch throwout rod, which has no oil in it. Although it does pass through the transmission, no oil gets into the clutch throwout rod.

But, engine oil can get past the main seals at the back of the crankcase, which seal on the crankshaft. This can happen if the seals are bad, or if the crankcase was over-filled with oil, or if the crankcase breather system is not working properly.

If it is the main seal (which BMW did have a problem with on early oilheads), engine oil does get on the tranny input shaft, which spins the oil out onto the clutch friction plate, and can cause clutch slippage at high loads.

The only way to fix that is to remove the tranny, clutch and "flywheel" (clutch basket/inner pressure plate) and replace the rear main seal. I did this on my 94 R1100RS at about 60,000 miles. The update calls for two seals instead of the one original seal.

[AntonLargiader]

Assuming your symptoms are as reported, it sounds like you have a problem at the rear input shaft bearing. Not unheard-of on M97 trannies. Drain the tranny oil; if it's burnt then you have an expensive problem. If not, then you still have a problem but it costs about $600 less.

[41107]

anton, should there be a seal on the far end of the input shaft in other words the end with the booty on it.the piston back in there has no seal and rather lets the oil go to either side of the piston.It is defenetly coming down on the rod,tranny was never overfilled and input as well as rear crank main both look dry.i have very well lubricated clutch spline and possibly clutchplate.(have not tacking the clutch out jet,actually looks dry in there from what i can see) clutch actually was slipping in 5 th gear accellarating thats why things came apart assuming clutch time.by the way its a motor unit from chips and anything can be expected with one of these bikes.

[AntonLargiader]

There's a seal between the case and the input shaft, so the throwout bearing area doesn't get any oil. What happens on some M97 trannies is that the input shaft gear eats its way into the rear bearing, and when that comes apart the back of the input shaft starts to move around, destroying the throwout bearing and letting oil get into the TOB area, which then migrates down the pushrod.

What does the oil look like? It's pointless to discuss this without that information.

[41107]

the oil is very black because i spiked it with moly,but does not smell burned.the obvio us concern i have is the constant accumulation of metal on the drain plug.got the bike with 32 k on it and find metal every time i change the tranny oil.CHIPS must have realy beat the crap out of this one.a little spiking i thought could not hurt.
well it looks like a good used tranny is in order.Or for the time being a felt sleeve around the rod to keep the oil in the back of the tranny till she completely craps out.
thats how it used to be on the older bikes, with the felt that is.
so thanks a lot Anton for the information,i was puzzeled by this one.

[41107]

just got thru reading and looking at your website anton.that rear input shaft bearing makes al lot of sense especialy with the metal that i am finding on the magnet.
great stuff you got there.

[AntonLargiader]

I haven't really written much about this particular failure yet, but several of us have found this happening on M97 bikes. At some point I'll take a few pictures of failed input shafts and add them to the page.

For now, you need to either get that tranny to a rebuilder or find another one.

Rebuilding means your local dealers or the independents who do this stuff regularly. It's not a given that your dealer will want to do this kind of work, though. It's always nice to have a local person do the work, but I simply don't know of anyone in your area. Guenther Wuest is in the next state but still 350 miles away, so it looks like you'd be shipping it no matter what. Offhand, I can think of several people who do this work (look in the IBMWR Independent Mechanics listing) if you want to go that route, including me.

If you have a failing rear input bearing, the felt sleeve won't do much for you. It'll just let the tranny run another 100 miles and do even more damage.

[41107]

i am going to tackle this one my self.wonna know whats going on in there anyways.got the tools and nothing to loose.if its the gear chewing its way into the bearing i would like to fix it good.not having to do it again sometime down the road.
i see the dealers have a regular kit for this.Must be a good money maker.
being a tool & die maker with acess to machinery i'll figure this one out.maybee a little gear undercutting is then in order to, if they are still any good.could never understand why bmw can build a smooth shifting tranny for the k bikes and such a lousy one for the boxers.i never have to preload the shifter befor pulling the clutch on both my k bikes.

[OfficerImpersonator]

could never understand why bmw can build a smooth shifting tranny for the k bikes and such a lousy one for the boxers.i never have to preload the shifter befor pulling the clutch on both my k bikes.

Everyone's mileage may vary, but I've found little difference in transmissions, shifting strategies, clutch use, etc. between my K75 and my RT. BMW transmissions are famous/infamous for being "clunky". Obviously there are more experienced/knowledgeable members who post here, but my personal experience is that the transmission is the weakest link on any BMW - not just R-bikes.

[41107]

i have a 1985 k100rs and a 2001 k 1200 rs on wich both transmissions are smooth as silk. got them brandnew and broke them in my self.