I have a 1984 BMW R100, ~1000cc, air-cooled twin, 5-speed with a cable-actuated dry clutch.
I went to ride it the other day and I couldn’t get the clutch to disengage. I can squeeze the clutch lever and see the pivot (rocker-arm like) moving in and out of the case, but nothing is happening w/ respect to clutch disengagement.
Operation of everything feels fine, just as it did when I parked it in the garage about 6 weeks ago. The bike has been performing as expected (wonderfully) every time I have ridden it (up-until now).
The cable was already adjusted to mfg specifications, but I tried tightening-up on it a bit in an attempt to give me more throw down low. I also tried using some external leverage (screwdriver and blocks of wood) to be sure that the lower pivot/lever is going in as far as it can. At this point I am convinced that the mechanical operations are working as expected, but it seems that the friction plate isn’t coming off the flywheel. Is this possible? Though I’m inside the garage, it’s been a damp summer and I’ve noticed some mold trying to grow on the textiles that have been (inadvertently) left in the garage. I’m suspecting that the moisture may be playing along in this saga, too.
Sounds like they have rusted together, not familiar with that clutch but I know a wide flat surface can be very hard to unstick if you can’t pry up on one end. My guess is that it is only stuck in a small area. Can you hold the rear wheel up some how and then drop it with the clutch lever depresed? The shock might break it loose.
Put the bike in second gear, if you can, and, with it in gear, try to roll it forward and backward, as forcefully as you can. Depending on how much driveline lash (slack) you have, you may get a couple of inches in each direction. This may break it loose. Regardless if they are that stuck together, you risk breaking the clutch surfaces, or at the least the binding is going to leave the clutch slip surfaces rough and maybe ridgy.
Old Bmw clutches are not like bike clutches (which are more likely multi plate) they are car type clutches and run dry (usually multi-plates run in oil) there’s a big plate and a plate that grips they can get stuck together and trying to jolt it to release is one idea. However Air head have a big following and there are a few good forums on their special problems where you will get good advice.
You are most likely overdue to lube the transmission input shaft splines, so drop the transmission and see what is going on in there. Airheads are easy to work on.
Thanks for the input everyone. I think I’ll try a gentle “forcing” of the components to see if something can break free. Well, I really shouldn’t use the word break, I guess. Ultimately, now I fear it is the splines as **Kevbo **mentioned. I’ve not touched them in the ~50k miles I’ve put on the bike. In fact, I’ve not had to peer any deeper into that power plant than the valve train for as long as I’ve owned it. I guess I’m due. You’re right… it’s an easy machine to work on. Thanks again.