tough downshifting

[JSBKC]

My R75/7 is tough to downshift. It is almost as if the bike needs to be standing still (or slowly rolling) so the down shift will occur. The clutch seems to be adjusted correctly. Is this a sign of worn syncros or some other problem? Thanks

[flash412]

Originally posted by KC_Bimmer My R75/7 is tough to downshift. It is almost as if the bike needs to be standing still (or slowly rolling) so the down shift will occur. The clutch seems to be adjusted correctly. Is this a sign of worn syncros or some other problem? Thanks No. There aren't any synchros in the transmission. It is constant mesh. Did you just get the R75/7 or has the problem developed over time?

I suspect that you just got it and are having an issue with the KLUNK when it goes into first at a standstill. Is that the case?

A more specific statement of your issue will help us to solve or explain it.

[JSBKC]

Yes, I am new to the R75/7 (I've ride R1050RT normally). The bike is difficult to get into first gear unless you are at a standstill. This doesn't bother me - I figured it didn't have syncros on first (similar to my Triumph TR3). It is also difficult to down shift from most other gears (5 to 4, 4 to 3, 3 to 2). Is this normal for this bike? Thanks

[srb]

If you are used to a modern gearbox, the airhead tranny will be a learning experience. The airhead gearbox is primitive. The key to smooth downshifts is to bring up the RPM's before downshifting. I like to blip the throttle to above 4K RPM before shifting down. And remeber to preload the shifter (take up the slack) before making upshifts. The airheads are a bit more of a 'feel' bike than their modern antecessors.

[Braddog]

Blip the throttle when downshifting, and work the shift lever smoothly, quickly, with the right amount power. I call this shifting "with gusto".

You may hear some clunks, this is normal.

[JSBKC]

So "clunks" are OK?

[PeoriaMac]

KC Bimmer says "So "clunks" are OK?"

Think of it as BMW's version of Harley's "potato-potato-potato..."

Mac

[sgborgstrom]

Like all BMWs made before the advent of the F650 the clutch plate rides on a dry splined input shaft that needs a bit of lube now and then. Difficulty shifting is one of the symptoms of a dry input shaft. Some high-moly content grease might go a long way to fixing this bike up.

Steve

[JSBKC]

Thanks Steve - I was wondering if this needed to be done. I'll track down some instructions and hope that solves the problem.

The other attribute I noticed is the clutch seems to 'grab' all of a sudden. Perhaps that could also be a sympton of a dry input shaft? thanks again.

[peteremsley]

KC, I asked about poor shifting (along with a bunch of my other newbie questions) in this thread:

http://www.bmwmoa.org/forum/showthread.php?s=&threadid=2474&highlight=new+owner

There is a link to a spline lube article in there. I still haven't done it yet as it sounded like a big job. My shifting seems a little smoother (perhaps I'm getting used to bike, or accepting the clunk)

Good luck.

[sgborgstrom]

KC wrote <The other attribute I noticed is the clutch seems to 'grab' all of a sudden.>

Susan's /6 had a grabby clutch as compared to my R75/7 and later R100S. I fixed it by putting in a new friction plate. My guess is that the 25 year old friction material had morphed somehow...anyway, replacing the old one improved the "feel" of the clutch.

Steve

[pmdave]

The 4-speed transmissions are a little clunkier than the 5-speeds, but unlike the Japanese transmissions, BMW transmissions require you to learn some new skills to reduce the embarrasing clunks. So, you can either make noise and pretend no one else notices your lack of finesse, or you can figure out how to adapt to the BMW transmission.

The "preload" technique mentioned is a big part of the process. When you're ready to shift (up or down) put your toe in position and actually put a little pressure on the lever just before you squeeze the clutch. When you squeeze the clutch, the shift dogs will zing right into the other gear (if you do it just right) You don't have to squeeze the lever all the way, just a quick snap halfway and back out again as the transmission shifts. It's important to blip the throttle on downshifts, to get the gears spinning at the appropriate speed so that you avoid the big lurch as you ease out the clutch.

With the bike stopped, stomping repeatedly on the shift lever (as practiced by many Jap bike riders) is not helpful to getting a BMW transmission to engage. The BMW shift dogs have a slight keystone shape to prevent the transmission from popping out of gear. Until the little holes and cogs line up, stomping on the shift lever will simply bend something. Instead, squeeze the clutch, preload the lever slightly, then ease out the clutch to the point where the gears begin to rotate. The shift dogs will drop into the detents, and you can then squeeze the clutch.

OK, it's brain vs. brawn.

pmdave :doh

[dlearl476]

Keep in mind you generally hear the "they all do that" reasoning from people who make their living repairing BMWs. Pmdave's assessment is right on, although I would venture a WAG that I move my clutch lever less than 1" when shifting, up or down. If shifting into 1 is a problem (I prefer to wait until I'm stopped) try "double-clutching" (pull the clutch, shift into neutral, let the clutch out, blip, pull it in again, and shift into 1)
IMHO, one of the joys of riding or driving classics is mastering 'classic' techniques. Once you've mastered the BMW box, you'll be ready for a vintage ZF "Crashbox".
Flash is too modest to mention it, but I think you'd be hard pressed to put it in words better than this. (http://faq.f650.com/FAQs/Gear_Shifting.htm#Clutchless%20Shifting)

[BIG AL]

Lubing the input splines really isn't a tough job to do, but the first time can be a bit intimidating. There are some great tech articles on the Airheads BMW Club website: www.airheads.org. Thoroughly read everything that you can find on the subject before starting, and by all means don't be afraid to find out if someone lives nearby that's done the job. I can think of many worse ways to spend an afternoon than sharing some food, drink, and spline lube. :D

[mrmaico]

The R65 I bought recently and which sat for years before I got it shifted great when I first got it but it quickly started getting hard to downshift. I lubed the splines and it shifts great again. I would almost guarantee you that is all it needs.

Barry