Hello all

Today I successfully dismantled the '86 k100RS forward to the rear main seal. Replace that tomorrow!

But on the way I found that the gear position sensor has disintegrated although still working.  Is there a fix for this or is replacement the only option.  I thought putting a section of PVC tube around it and filling will some sort of epoxy.



The other issue I had was the clutch housing cover was quite rusted and proved a real battle to separate it from the clutch housing.  Although the pins aren't corroded they are very tight in the clutch housing.  Can they get bent on assembly or removal?

What plates are factory marked?  I looked at clutch kits and they supply the diaphragm spring, pressure plate, clutch plate and the housing cover.  Therefore I consider the clutch housing must be "true" i.e. balanced and it is only the pressure plate and housing cover which have factory marks on them to be fitted 180 degrees from each other.

My concern is if I fit the housing cover and the locating pins are bent that the next time I go in that it will not come off!  As said it was a real bugger to get it free this time.

Any suggestions would be gratefully received, at 850 AUD for a clutch kit, I'd rather use what I have!

The clutch plate is at 5.2 mm so will be going back in.  I am surprised it is this worn, recalling a new plate to be 5.5 mm, as the bike only has 11,000 km on it!

"They all do that."  I've taken oodles of K clutches apart and it's always a challenge to separate the clutch.  I wouldn't worry about those pins.

What I've found works well to get a K clutch apart is to use one of these mini nail pullers working around the outer rim of the clutch assembly.

My RT got a new rear main seal at 78k miles.

The only clutch components replaced were the friction plate and the necessary bolts. The entire of the rest was deemed suitable for reuse. For the plate I bought a Sachs plate. There is no such thing as a BMW manufactured clutch plate, Sachs make them for BMW.

I did replace all the seals O rings etc etc when I was in there, swing arm/driveshaft boot, clutch pivot bearings/boot and all new clips along the way.

I'd check those pins very, very carefully. If they bent on the way out - even a tiny fraction - the clutch will not go back together. They're made of a soft metal, so straightening them isn't too much of a problem but be prepared to chase and chase and chase... When it happened to me, I used an 8oz hammer to gently tap the pins straight again but it took a lot of patience and checking and rechecking before the two halves slid back together.

Secondly, clean any crap off them and from inside their housing. A well-fitting, finger-turned drill is good for that.

I used a sharp wood chisel and gently tapped on it working around the circumference of the clutch for about five minutes to get mine apart. 

Have some paint and a Q-Tip handy to mark the parts as you take them apart.  The Q-Tip makes a nice dot and you can toss it when you're done.  Instead of having the marks at 120 degrees like the factory marks, I marked mine so the marks all lined up with each other.

Before you try to remove the Gear Position Switch, you might want to put some CA glue on it to help hold the crumbling bits together.  You can get the CA at a hobby shop for guys who build model airplanes.  Gently clean the outside of the switch with rubbing alcohol and an artist's paint brush to remove as much of the grunge as possible.  Put the glue on and let it soak in a bit.  Then set it with the catalyst you can get at the hobby shop with the CA glue.  Once it's glued up, you can safely remove it.  Ditch the original screws and replace them with Allen screws.

If I was going to epoxy the switch, I would reinforce the epoxy with some small pieces of fiberglass cloth.  The best stuff for the job is the very fine cloth the model airplane guys use.

I agree with Point Seventy-five's advice on the switch. The outer shell of the switch is a plastic cover for weather protection and needs to be first reinforced with a fabric to retain its shape and a sealant to make it waterproof. An alternative to fibreglass cloth could be heat resistant polymide tape (aka. kapton tape) used for electronics plus an outer coating of silicone sealant. If the integrity of the shell is compromised, then CA glue and reinforced epoxy would offer structural strength and waterproofing.

+1 replace the bolts with stainless Allen bolts. I replaced mine nearly 20 years ago and coated in red Plastidip it's been going ever since.
Regards Martin.

You will find that the crappy stuff that is crumbling awqay is the remains of a rubbery cover that was supposed to be waterproof. Carefully scrape it away then if necessary the housing can be parted and the innards cleaned then clipped back together. Be careful not to let the springs and bits fly and hide.  I then cover the whole thing in sikaflex (which can be removed with difficulty and a very sharp knife) it is ready to be replaced and wont leak.

Thanks for the advice everyone.

So Dai, how does one gauge when the pins are straight, or is it just see where they go into the housing holes?

Tesla13BMW wrote: or is it just see where they go into the housing holes?

Pretty much so, if they're not obviously bent.