1978 R100/7 Transmission: New thread for an old problem

If anyone has some experience with this issue, I am looking for someone who can rebuild the transmission with this specific problem in mind.
Background: From 2010-2012 I completely restored a R100/7 and documented the entire process here on the forum. An awesome experience, but at the end, I had a problem in 2nd gear with the transmission. Cue the Youtube cut!
https://www.youtube.com/watch?v=KIHh1UUtTxk

So, after some research and a lot of exploring with fellow airheads here in San Diego, back then we found two other bikes that had the same problem, but in different gears, not 2nd gear. No one was able to resolve it.

Years later my beautiful bike has been a garage queen for years. Now, I'd like to crack this nut again: a helpful comment on the Youtube channel was this:

Robert Borchert
2 years ago (edited)
Just spotted this video albeit a little late! BMW uses large cogs to move the shift forks, with a nylon roller holding the cog in position. The gear dogs are being pushed apart under load. There's likely wear in the mating faces for the second gear. If the nylon roller on the edge of the cog can move away from the cog too easily, this is also possible if the return spring for the roller arm is weak. Also check the shift fork for a bend or wear. It's hard to do, but simple if you compare the dimensions of the fork against a new one. Simply mount it on the shaft and measure against the work bench with the shaft secured.

I wanted to ask the forum: What do you guys think? I am ready to pull that transmission once again and ship it off, but only if I have a reasonable chance of success: This is after a complete teardown and rebuild here at a shop in San Diego back int 2012.. so maybe I just took it to the wrong shop.
Cheers, and thanks for reading.
K

In California your go-to guy/shop is Ted Porter's Beemer shop. If you were in Kentucky I would say Tom Cutter but in California it is Ted Porter.

Go with a proven shop

I am with Paul on this subject 100%. There are a LOT of people who claim or think they can rebuild airhead transmissions/heads/engines and have no clue or tools to do the job properly.

I got educated by Ted Porter not too long ago watching his website video regarding rebuilding airhead heads.

Yep, I feel for you to have spent a chunk of change to have a problem repaired only to find it wasn't or perhaps now worse. I don't suppose you got a refund for the cost of the rebuild the first time.

Good luck, with the next rebuild. Let us know how you make out, we like to hear outcomes of threads. Cheers, St.

I’m not sure Ted Porter’s shop is doing transmissions any more; they seem to have focused on head work and suspension work. If they aren’t doing trannies then another good option in the west is Hansen’s BMW in Medford, OR.

Best,
DeVern

That problem should not be hard to rectify. I will say that it's not a common issue, but along the same lines it will be traceable to just a few internal components. I dealt with a LOT of those issues with the R1100 transmissions and know where to look. The previous replies to this thread are generally in the right direction.

That said, repairing a '70s transmission has its challenges and may involve using the best available used parts and upgrading to the shift kit components. Not necessarily an inexpensive thing.

AFAIK Ted is not working on these but there's no harm in calling. He has referred some of that work to me and probably refers some to other shops as well.

If you want to talk about this, call me at the shop (link in my sig) during working hours Eastern time.

Thanks everyone!
The transmission is at Bob's Motorwerks in MT thanks to a referral fro. Ted Porter.
Bob says everything okay inside, but will replace two slightly rounded gears, although he wouldn't have if there was no problems.
A real mind bender this one.
Will post again after a test ride!

Update, 1978 R00/7 Transmission: jumping out of 2nd gear

Bob Clement of Bob's Motorwerks in Montana has finished up the rebuild as of yesterday: some of his observations: yes, the dogs and the holes in the matching gears for 2nd were rounded, so there is a "new" (on hand) 2nd and 4th gear now.
The pictures of the gears Bob put in...
However, he said if he didn't know it was a problem he wouldn't have replaced them. I should get the transmission here in a few days and I can compare the two sets of gears with pictures for anyone interested. replaced quite a few items, including two bearings that were not up to his standards, and the various springs/shims.
What a joy to listen to a pro who identifies the tiny little variations that were obviously missed when I had this thing rebuilt down here in San Diego!
Anyway, I'm in the middle of getting the rust out of the tank... rebuilding the carbs... cleaning everything up, and a new battery should be here soon. Replacing the valve cover gaskets since one of them was puffing away the last time I rode it.
Thanks again for all the input everyone! I think another "back from the garage" thread is in order once I hear this thing start up for the first time in 7 years (pretty sure 2013 was when I took it out for the last time).