Stopped Shifting

[MartyH]

:cry While on a road trip last week my 1975 R90 just stopped shifting. From a stop I went through the gears to 4th gear. When I attemped to shift to 5th nothing happened. I tried to shift down and still nothing. The only thing felt through the shifter lever is the return spring pressure. I hobbled back to civilization in 4th gear and called for the truck. I suppect a broken shifter fork. Any other suggestions? I plan to pull the transmission today and look inside. (PS, this is my first posting. I hope I get it right)

[James.A]

The early 5speeds were known to have a weak detent spring, the 5speed kickers particularly. How many miles on the bike? Be sure to poke around on Airheads.org and ibmwr.org for tech articles before taking apart your transmission. Specific tools and proceedures are to be utilized.

[pmdave]

The good news is that the transmission worked for 30 years. Plus, pulling the transmission gives you a good opportunity to check the oil pump, replace the rear main seal, and lube the input splines.

If you've never taken an R transmission apart, I suggest you just clean it up and ship it to one of the rebuilders.

If you are determined to overhaul the transmission yourself, Matt Parkhouse did a complete explanation in Owners News over the past couple of months, complete with lots of detailed photos and advice. I think it was March and April issues.

pmdave

[MartyH]

Thanks for your comments on my tranny. Well it is now apart. James, you were very nearly right. It was the pawn spring that was broken. Everything looks ok. I should probably dig deeper, but here on the north coast of Ohio, riding season will finaly start in earnest this weekend (maybe, it snowed today). I am really anxious to get some riding in ( I just retired a couple week ago) and I don't want to take a chance of having to wait weeks to ride to do a major rebuild. Yeh, I know I will probably regret it later.
Thanks again, Marty

[flash412]

"There is never enough time to do the job right, but there is always enough time to do it over." - Tod Ode

[Markst1]

Marty,
Let me know when you are back on the road. If you want to get together, I'll ride my airhead out to Chardon and we can introduce the /6s and ride a bit together. I'm just down the road in Shaker.
Theo Marks

[R100RS]

I am really anxious to get some riding in ( I just retired a couple week ago) and I don't want to take a chance of having to wait weeks to ride to do a major rebuild. Yeh, I know I will probably regret it later.
Thanks again, Marty
Sounds like a reason to have a second bike! Seriously, I'd take a good hard look in there (or send it out or find someone knowledgeable in your area), feel all of the bearings, you DON'T want to have to do this again. Definitely replace all of the seals (input, output, shifter). You may also consider replacing the nylon roller with a metal one from a K-bike.

How was the oil when you drained it? Any signs of water? What kind of metal shavings were on the drain plug and how much? Were they soft like slurry or granular like sand? If the latter, your bearings are most likely in need of replacement.

The other thing you will want to do is to check and re-shim the transmission bearings. Apprarantly, there have been changes to the cover gasket which results in the end play being wrong when putting a new gasket in. Also, BMW was not very good about getting the end play correct in the first place. Plus, wear from use will change it. I just finished rebuilding a '75 /6 tranny and the end float was way off.

Obviously, check for any leaks from the engine rear main seal, and you may want to replace that while you're in there. I opted not too. A proper lube of the input shaft splines is of course required.

[magoo]

There's a shop in Lorain, Cobb HD/BMW repair. The owner is Turp Cobb he is the current president of BMWMOC, and is very knowlegeable about airheads. He also may have parts on hand.

Doug Mc Gee

[MartyH]

Thanks to you all for the VERY good comments. I got it all back to gether. After measuring for the shims I had to remove one shim on the output shaft bearing. I replaced all the springs on in the shifter mechanism. I think I put the trrow out bearing back to gether correctly after cleaning it, but???

Everything shifted great and felt fine. I took it for a test ride (about 5 miles). Seemed fine on the ride out out. On the way back home the cluch started developing slack. by the time I got home the clutch lever would barely disingage the cluch. I re-adjusted the cluch at the rear of the transmission (throwout bearing lever). It felt normal with the engine running, no noise. Howerer, at a slow idle I could hear the engine lug down slightly. I plan to pull and replace the throwout bearing. Any other suggestions???

Mark, feel free to call me 440-285-9664. I hope to be back on the road soon.

Marty

[James.A]

...but it's never stopped me in the past. I recently swapped out transmissions in an R75/5. 4 speed for a 5 speed. It took three rides and re-adjustments until the clutch action settled in to the way I like it. It is not hard to do in a parking lot if you have a few tools with you. I'd give it a couple more short trips to see what happens. It sounds kooky, but it worked for me. Always try the easy stuff first.

[MartyH]

Just to complete the saga. The Clutch adjustment problem was a loose nut on the end of the wrench. I Put the throw-out bearing back together wrong. I replaced the bearing and just like Willie, "Back on the road again." Thanks for the comments.

[Markst1]

Great to hear that things are all in order. I'll give you a call this week. Maybe we can get the siblings together for a family reunion and do some riding together.
Theo Marks

[AntonLargiader]

Just to complete the saga. The Clutch adjustment problem was a loose nut on the end of the wrench. I Put the throw-out bearing back together wrong. I replaced the bearing and just like Willie, "Back on the road again." Thanks for the comments.
I know exactly what you did. Have you changed the tranny oil? All of that aluminum went somewhere, you know.

[WooDmEn]

When the spring breaks, there is a technique whereby you can lay the bike over on the left (I think!!!) side, and hand-shift the tranny into like third gear and be able to lomp home. Something about gravity re-setting the shift-plate, in the absence of the spring. "Might" be the right side!!!

Stevie Michaels, of Pittsburgh, sells a neat little stainless steel doo-hickey that such an afflicted rider may insert into the Airheads' tranny's fill-plug, and fiddle the shift-plate into the gear of choice in order to limp home.