Hello,
I just picked up a really nice 85 K100rs with 43000 miles on it. My first BMW. Runs good, clutch works good, shifts good UNTIL.

I have 24 miles on it, yes 24 miles. I shifted into 5th, something didn't seem "right". I then downshifted into fourth, and something definately was wrong.

I now have only 5th gear. There is "drag" on the other gears, but even with the clutch engaged I can spin the rear tire. This drag is the same regardless of the cluch engage or disengaged so I am guessing the output side is ok.

The transmission is not shifting into 3, 4, or 5th very easily now. (on the stand without engine running)

I am guessing I will be pulling a transmission.

Any advice as to what went wrong would be greatly appreciated. Miricle cures without pulling the transmission get a 6 pack

TIA

Ddub

I just lost my reply to you, was trying to insert a link, I dont know what your issue may be, but there are a lot of things involved with removing the transmission and lots of care must be taken. If you can drain the oil and look for particles that would be a good start.
I tried to type in a total coverage of the removal but as I went through the process I found myself finding important steps that I left out in something listed before.
I'm willing to bet that somehow the shifter Y's have become worn out or broken, that may not be the case though. I do not have any serious photos of the inside of my transmission. I just know that its removal can be pretty tedious. If you have your heart set on pulling it off and getting inside ill post what it involves. hopefully its something really simple inside.
http://www.maxbmwmotorcycles.com/fiche/MainDiagrams.asp?mospid=47861
diagram #23_0275 shows the Y arms and the drum, and the spring and bearing you cant lose.
covers pretty much all the parts involved.
but taking it off/apart can give you access to spline lubes, boot replacements(they are old and probably leak), and starter cleaning(its really simple and straight forward). There are a lot of cautions you will have to take though, some bittie parts are easy to lose.
Check the oils condition. If you have particles, with a green coating and they are not magnetic its the Y's. hmm, im not sure if they are aluminum or not really....the gears are as robust as anything ive ever seen. Let me know if you want me to ramble on the disassembly of the thing. If one of the Y's snapped that can cause lots of drag on any of the gears. I just cant say for 100% sure what the issue could be, the shifter moves an arm with 2 catcher that rotate a drum, that moves the Y's forward or backward to complete each shift, that complete set of stuff, is the weakest link in the transmission, its robust but nothing like the gears themselfs. The only way they could break is from overforcefull shifting while not syncronized. maybe some ride shaft bending, and then bending of the Y's.
Good Luck
Phil

Gezar,
thanks for the reply.

I will be draining the lube tonight in a BRAND new oil pan and looking at it. (I am cleaning the shop today in preparation for pulling the transmission). Too many projects going on! I have one car, 7 snowmobiles, a lawn mower, and an ATV in various stages of mechanical needs in the shop as we speak This obviously was not planned.

Looking at the parts break down that you sent me too, I think you are correct. Those diagrams seem to be a little clearer than some of the others that I had seen and have some "labeling" of the parts. I'll bet that the 5th gear yoke is damaged and won't move it again.

I'll be pulling the transmission regardless from what I am seeing. I guess I am trying to evaluate my options and hopefully made a wise choice. Fix this transmission which is why I was trying to get some ideas as to what happened so I can be prepared. From what I see when I look at parts prices BMW is proud of their transmission parts which has me a little nervous. Go with a used transmission (I have a couple located already) which is looking the most promising, or if the numbers don't come out, part the bike out which would be a short and sad ending for me and this bike.

The part I don't like about a used transmission is that you do not know if the "good" transmission that you are getting is much better. The labor is the same to install a transmission that works properly as one that does not.

As for "how" this happened I don't really know. I was having fun seeing a LITTLE of what the ole girl had in her as I accelerated down a country road. I won't say it was the smoothest shift that I had ever accomplished, but nothing that I would have thought would have broken anything.

I know my way around a wrench so pulling the transmission doesn't scare me. Even pulling the tranny apart doesn't scare me. With that said, in my old age sometimes I let the experts do what they do best and this may be one of them. So I may ship the tranny to someone IF fixing the transmission seems like something that would be econimical to do. I just don't want to ship it somewhere if we know that the parts bill is going to exceed what I am willing to spend. I am at least 250 miles from a "BMW" mechanic, so taking the bike to one isn't exactly easy.

As for pulling the transmission, I have a pretty good idea as to what has to happen. I have a Clymers manual and located a few online tutorials. 15 minutes it should be out

On the bright side, I guess I'll get a crash course on what makes a K100 tick and look everything else over!

I'll post what I find tonight with the oil.

Thanks Dennis

lets hope its just simple, probably nothing you did, or that the previous owner did. just time has its way with most things in this world. yeah, everything with a BMW logo on it is astronomical. I dont think its going to be that bad for you though, a used trany isnt going to be a bad option if you can part it out, mix n match. if it is one of the Y yokes...I guess they are called.. and it broke to pieces, then im betting the gears acted like a meat grinder and made it a molten mess but probably not a huge issue. there are some shops that deal strictly with wrecked and parted bikes, that may have the parts you need for cheap I bet. have fun and good luck
phil

Well it doesn't look real good for the home team. Lots of Aluminum and some steel. the steel is probably just normal wear and tear.

I hope there was more oil in there then what it looks like, and yes there will be a small bit of filings on the plug mag. but no aluminum should be in there. youll know more once you get into it

Gezar,
Yes there was more fluid than shown. I lost some because of the dag nabit center stand, and I poured some out for a better picture. Or should I call it a "worse" picture

I am really hopping it is something simple.
let us know as you go along.
phil