I posted a note on the net and got back 6 unanimous replies that my pawl spring in my transmission had broken. The part costs about $1, but I've heard estimates of $200 to $600 for labor. Being about 2 hours away from my local dealer and no way to get it there except by riding it all the way in 2nd, I took this as an excellent educational opportunity!
Both Haynes and Clymer describe how to remove the tranny by moving the engine forward in the frame. This requires removing the exhaust system which I didn't really want to do because 1) I don't have an exhaust wrench and 2) I have this fear that my exhaust nuts are so corroded on there that removing them might damage my pipes. Don Eilenberger gave me the idea that I could remove the tranny by removing the swingarm instead and leave the engine in place. I opted for the swingarm method.
For the output flange extractor, I borrowed from a friend a harmonic balancer steering wheel puller which can be picked up at most auto parts stores (or Sears) for $20. I had to pick up 2 8mm x ~3inch fine threaded bolts to attach the puller to the output flange. Using this tool, one can pull on two of the four output flange holes at once. Last week, someone posted a note saying they screwed up their output flange using only two holes. Others + the Haynes manual said it could be done. This person said that he had to buy a rebuild that was pretty costly to fix his problem. I've priced how expensive a screw up is, and actually consider the cost/risk factor cheaper than buying the special tool. A new output flange is about $90. If the output shaft were damaged, which I'm not sure how this could easily happen, it would set me back about $150 for a new one. Determined to be an other, I let the output flange soak in liquid wrench for 36 hours. With the help of a friend (Terry Mclaren), Here is the repetitive process we followed:
We repeated the whole process about 4 times. On the fourth time when we tapped on the puller with the hammer, the output flange came free. Just like the manual had said, "When the output flange releases, there is a loud crack like metal breaking. This is normal." I'm glad I had read that. It's a bit of a shocker when it finally breaks free.
There are nine alan screws that hold the cover into place. After removing them I bopped the cover a couple times with my rubber mallet hoping I would get lucky and the cover would just pop off. no such luck. The repair manuals say it may need to be heated to 80-100 Celcius. The two methods I've heard to remove the cover are to bake it in the oven, or use boiling water. I opted for baking. There was a note on the net from someone concerned about leaving the oven smelling like hypoid oil afterwards. no problem. However, I made sure that the tranny didn't touch the oven nor would any oil drip onto the oven if it should leak out.
I put the tranny in a baking pan lined with tin foil and then stuck it in the oven for 40 minutes at 225 checking on it periodically. It takes a while to heat up all that metal. Pulling it apart wasn't easy. The rubber mallet helped separate it enough so that I could apply a little gentle prying force. In the end though, I had to persuade the cover to come off with my rubber mallet. The sharp edges of the tranny cover shredded my rubber mallet and left rubber shavings everywhere. I'll have to remember to wash out the tranny with some hypoid oil to make sure I got out all the little rubber bits. The bearings on the input, output and intermediate shafts fit into the cover and are what hold the cover tightly closed. Since the tranny took so long to heat up in the oven, much of the heat may have transferred to the bearings reducing the thermally caused gapping between cover and the bearings. Next time, I might try putting some boiling rags on the middle of the tranny cover where the shaft bearings mount. (later addition here:) with hindsight, experience, and asking some experienced mechanics I would suggest carefully using a propane torch to apply an even heat across the cover despite what Haynes and Clymer say. The cover does not need to get above 100 Celcius and probably shouldn't.
The net diagnostic was correct. The pawl spring had broken. the coil of the spring was still wrapped around the pawl axle. However I haven't located the broken portion of the spring. I'm hoping it drained out with the oil. I'll be checking for this.
I removed the two bolts that hold the gear shifting mechanism in place. Everything on the gear shifting mechanism is held in place by circlips and e-clips. My needle nose plyers weren't quite small enough to remove the circlips. Without the right tool, it's a drag. I picked up a circlip removing tool at the hardware store. It took me 5 minutes to dissemble the whole gear shifting mechanism... amazing what the right tool for the job does.
Noemi Berry mentioned a gear shifting upgrade kit that I ordered for $70. Also, she said that Cal BMW recommended replacing the nylon roller on the shift mechanism with the metal roller that is installed on the K bikes. The upgrade kit comes with the two cam plates, shifter lever, pawl and pawl spring. It's intended for bikes from '74 to '84. I've been told that this was stock in the 1983 and later R65LS. I compared the shift kit with what came with my bike and found that the output shaft cam had deeper shifting recesses for the roller which I guess would make it more difficult to slip out of gear. The intermediate shaft cam looks identical to the original. The shifter lever looks stronger. The pawl looks a bit different. The new one has an extra run of metal along the back which looks like it would prevent it from flexing back too far where it could hit the intermediate shaft cam. This may save the pawl spring from being over flexed and breaking again! I noticed that the Clymer blow out drawing of the shifting mechanism has the old pawl while the photos are of the new pawl. The cause of all my troubles, the pawl spring, is being replaced with a thicker gauge spring that looks like it should be more durable.
I noticed that the rear intermediate shaft bearing doesn't spin as freely as the other bearings, however, there isn't any roughness. Haven't decided yet if I should replace it.
Fortunately I have another bike (the R100GS) and am not in a hurry. Due to other things going on, I've only had about an hour every other night to work on this. This works well when one has to rely on mail order for parts. I started taking this apart about 2 weeks ago. However, it probably would have taken me about a full day to get this far, less if I didn't have to make some tools and run to the hardware store. I'm taking my time studying the parts as I go...
For the next two weeks it looks like the bike will be sitting in pieces in the garage until I get some free time to put it back together again.
Dave Thompson firstname.lastname@example.org (http://www.spyglass.com/~davet) '82 R65LS '92 R100GS '81 R80G/S Champaign, IL