Difficulty down shifting

[getset]

78 R100/7

I am having a little trouble downshifting from fifth. Around town it is fine in 1st through 3rd, but when I get it up to speed for a nice ride I have trouble down shifting. some times I have to come to a complete stop and rock teh bike back and forth to shift down. I recently changed all the fluids and lubed the splines. This bike is new to me so I will check over all the clutch adjustments tomorrow, but thought I would poll the group for any advice.

THanks

[20774]

I was going to mention lubing your splines, but you did that. Any chance you got too much lube on the splines? I've heard that hard downshifting can be related to the clutch disk hanging up and making it difficult to match speeds between the spinning input shaft to the tranny and the output shaft which is being turned by the driveshaft.

[getset]

That is a very good possibility, as I wasn't quite sure how much to put on there, and is it ever a pita to see in there. Do you think i should clean it off and try again, or should I just ride it and see if it gets better?

[20774]

How did the check of the clutch adjustments go? I was taking a stab at too much lube, but unless you really lathered it up, about the only thing that might happen is that some gets slung off and onto the clutch disk, creating a whole 'nuther problem. Or possibly pushing the lube back into the tranny input seal. BTW...did you remove the transmission for the spline lube or just slide it back an inch or two?

Exactly what happens when it's hard to down shift? Is it just stiff or do you grind gears? I wonder if the bushing on the foot lever where it goes into the case is worn and creates some added drag and misalignment making it difficult to shift. Be sure that the shift shaft remains in its central position through all gear changes. Try this out standing next to the bike and turn the rear wheel.

[AnnapolisAirhead]

My guess is that he didn't remove the trans to lube the splines (e.g. "..and is it ever a pita to see in there.". I thought too much lube would make the clutch slip...but it can affect downshifting too? :dunno

You didn't, by chance just install a different side stand did you? I tried a Brown's and the shift lever hits the rear engine mount nut so I couldn't downshift. Sounds like its probably NOT your problem since 5th to 4th is the issue but I thought I'd mention it. Doesn't seem to affect some folks, but then I felt the under the inside edge of their shifter and it has been worn.

[20774]

My guess is that he didn't remove the trans to lube the splines (e.g. "..and is it ever a pita to see in there.". I thought too much lube would make the clutch slip...but it can affect downshifting too? :dunno


Ahh...I see the snippet about peaking inside there; you're right, just pulled it back a tad to clean/grease.

I wondered how a spline lube would affect downshifting more than upshifting and posed the question on the Airheads list sometime back. From what I recall, it has to do with how much easier it is to match speeds between engine (crank connected to the tranny input shaft) and tranny (rear wheel connected to the output shaft). I envision that if the splines aren't lubed (or maybe too much??) that the clutch disk might still be seeing some engine RPM despite having pulled in the clutch..i.e., the disk didn't separate as cleanly as we think, thus it's still being "influenced" by the flywheel and thus makes meshing the gears harder.

I'm not sure I really understand what's going on...I don't use the engine much for braking and have never really had this type of situation happen to me.

[AnnapolisAirhead]

Admittedly, I haven't ventured into a clutch yet, but I'm building up courage for whenever I need to do it.

[skiteach]

It's curious that it's only down shifting from 5th. If it were all gears, esp 1st then I would be inclined to say clutch was hanging on input shaft ( it may still be that ). Haveing driven several cars where the input shaft was stuck in a failed bearing/bushing (the ones that live in the crank and support input shaft), clutch doesn't do much in these cases and all gears are "hard" to shift, unless speeds are matched. In this case it was stated that 1-3 were ok, what about 4th? There may be a mechanical (internal) reason that 5th is so hard to disengage, ie; syncro/dog wear, bearing failure or shimming issue. By sliding the trans back and lubing the little accesible part of the shaft, it would be hard to check for wear on input shaft and easy to dislodge some of the "dust", from friction disk wear and capture some in the lube, which could cause some stiction on splines. I'm thinking that One would clean the area with brake kleen, dry and then lightly lube the exposed section of shaft.

[getset]

Thanks for all the discourse folks.

Yes I only separated the tranny to get to the spline for cleaning and lubricating. bought some small brushes trimmed the bristles so they were stiffer. One for cleaning and one for lubrication. I can't imagine I put to much on.

I found that there wasn't enough free play in the clutch so I adjusted it, but it has been raining the last couple of days. Hopefully I can test it out tomorrow after work.

Shifting issues; It does only seem to be in the higher gears, and only after I have been cruising in fifth. Then, I will be approaching a stop sign and begin to down shift and find myself unable to . I then have to pull in the clutch coast to a stop and rock the bike back and forth to get it down into first. I never have trouble around town, or even if I am in fifth for a short while. It only seems to do it after ten minutes at 65 or so.

Hopefully I will be able to test it out tomorrow.

It just rains so much in June in MT.

[20774]

Shifting issues; It does only seem to be in the higher gears, and only after I have been cruising in fifth. Then, I will be approaching a stop sign and begin to down shift and find myself unable to . I then have to pull in the clutch coast to a stop and rock the bike back and forth to get it down into first. I never have trouble around town, or even if I am in fifth for a short while. It only seems to do it after ten minutes at 65 or so.

Do you pull in the hand clutch lever, coast all the way up to the stop sign, and then start to find the lower gears? Or do you brake a little, downshift to 4th, slow some more, downshift to 3rd, etc.?

The latter way might be better in your situation. Me, I can do the former and often do. Or I'll continue to hold in the hand lever, and downshift as my speed bleeds off to the appropriate gear for that speed. That way, if the light should change (if that's what's controlling the intersection), I can just let out the hand lever and go on.

[getset]

I do the latter. I usually use the gears to slow myself down. That is until recently, when I am unable to. I rode it around a little bit today, but haven't had the opportunity for a longer ride as my house is about a mile from my office. I will turn it loose after work and see what becomes of it. Initially the clutch feels a little more grabby. It seems to grab quicker, and I haven't had any trouble shifting around town, but then I never really did. While I was messing with the clutch, I noticed my throttle adj. was loose at the carb, so I adjusted the free play in those, and it seems to tun quite a bit smoother now. What other discoveries lie ahead? This is my first BMW, and I already want more of them. I find myself still looking on craigslist, and trying to talk friends into buying the good deals I find. They are just so dang fun even when they're not runnig perfect.

More to follow.