90w weep

[rkellyh]

I'm a happy new owner of a  86 monoshock R65.  What a nice bunch on this site! I've solved a few problems already thanks to the info here, but I'm stumped by a 90w drip from a mysterious nut/wire combo on the bottom of the tranny, but not easily seen (or replaced?).  It's where  the crankcase is actually behind & under the tranny and there's a small grap where I see this nut.  (not oil pressure sender, not nuetral indicator??) any ideas?   Also, when I changed gear oil, I went to 75/90w, and perhaps that started this drip.

[Bob_Roller]

That nut and wire assembly is the neutral indication switch. You guessed it right, that it's not easy to replace, actually after doing it once, next time it won't be so intimidating. The cost of the switch is around $25 US. If you can get a wrench on it and give it a little snugging up, don't get too enthusiastic about it, as it's only made of aluminum, and so is the transmission case, not very forgiving of over torqueing.

[Justin B.]

If it is not really making a mess of things I would just leave it and change it next time you have the tranny out/pulled back for a spline lube.  Or, if it is leaking badly and you have never lubed your splines (and don't know when they were last lubed) this may be a good time to kank the tranny and kill two birds with one stone.

When replacing the switch verify that it is functioning properly before reinstalling the tranny...

[Rob Valdez 79 R65]

If you do end up needing to replace the switch, one of the 'easy' ways is to pull the transmission.

Unless you know the previous owner real well, and have a maintenance record, as a new owner you will want to check on the splines on the input shaft of the transmission.  This is not such a critical maint. item on the mono-shock bikes as it was on earlier models, but it is still good baseline information to have.
The splines should be cleaned well, checked for wear, and if all is well, lubricate the splines (on the shaft only, not on the mating splines on the clutch) and with your new neutral switch in place, put it back together!

You can also check on your tranny input seal at this time, and to a degree, check on the health of the rear main seal.  If you own the bike long enough, you will need a new rear main seal at some point.  It is behind the clutch/flywheel.  Don't ever remove the flywheel without first blocking the crack to keep it from moving forward a fraction of a mm.  Bad news.  We'll get to that later.
Also behind the flywheel is the cover for the oil pump.  On the older bikes, at least, ANY time you pulled the tranny, you pulled the flywheel also so you could check the four bolts on the oil pump cover.
I have never found mine to be loose, but this is a common source for an oil leak.  It has a small o-ring that is replaced whenever you are there.

I am totally clueless when it comes to swingarm pivots on mono-shocks.  
The reason I say this, is because on the older bikes, you have to drop the swingarm to remove the transmission.  I wouldn't be surprised if the mono-shock bikes are the same.

Good luck with it!  They are fun to work on.

[rkellyh]

I was reading earlier about the spline lube & I believe I do have to drop the swing arm & align on my monoshock - sounds like a fun day.  It's just a drip or 2 a day now - hot or cold.  Still, I sure hate the smell of burning 90w!  Thanks for all the great info, I'm looking forward to becoming a  'student' of this bike!  

[Chris_in_BC]

I was reading earlier about the spline lube & I believe I do have to drop the swing arm & align on my monoshock -

Yes, you have to remove the swingarm, but the procedure is exactly the same as on Rob's earlier twin shock. Just a bit easier as you have more room to move around. And the alignment is nothing to fuss over. Very easy to measure it so it is roughly centred. Doesn't require surgical precision. We are dealing with glorified tractor engines (oops I mean BMW) after all.

[Rob Valdez 79 R65]

I wonder if Duane's axiom 'center the driveshaft in the tunnel, rather than centering the swingarm in the frame' still applies with the single-sided swingarm?  Don't know why it wouldn't.

Oh, and you could replace the switch by just sliding the tranny back until it hits the swingarm.  That would be a quick fix for your leak for now.

Be sure your sealing surfaces are clean when you put on the new switch.  And like the guys said, make sure it works before you put the transmission back in.
And get the correct switch - BMW had two versions over the years.  Your part# is 61 31 1 243 097

You can peek in and do a quick visual of the splines while it is there.