Boxerworks.com

Yikes- It's been so long since I've read or posted here. I wonder if anyone remembers me

Anyway, finally going to rebuild 1 or 2 of the 3 trannies I have in the garage. I've done it 2-3 times in the past, but it's been a long time. Wondering if anyone has:
1) a quick reference list of the bearing and seal #'s
2) Source for the bearings (i think i got my bearings and shims from Ed Korn last time, or maybe Hucky's, or maybe a local bearing supply).
3) I seem to remember replacing the little nylon shift wheel with a metal one from a K-Bike. Anyone know?
4) Do folks still automatically replace the pawl spring?

Thanks all,

Don

'92 R100GSPD
(sold both my ST's, the RT, the R65, and the R100)
'04 R1150RTP

Hi Don,
I can't help you with the list, but I thought I'd say hi.

Hucky has kits with all the bearings and seals needed: http://www.bmwhucky.com/007523.html

Thanks guys, and Hi Jeff (long time, no see!).

I probably don't need all bearings, but will know more when I look closely. Anyone have a suggestion on the little shift mech wheel?

Don

Here's a link that has a lot of info on overhauling transmissions, including a list of bearings and seals for both 4 speed and 5 speed transmissions:

http://www.largiader.com/tech/airtrans/




Ken

It makes no sense to not change all the bearings while in there. 89 pounds for all bearings from Motobins.
Complete gasket and seal kits from Motobins as well.
Re the nylon wheel change, I was going to change for the bearing option until someone mentioned that they had used the bearing and didn't like the 'feel' of it. I think I can grasp what the person was saying.....and renewed the nylon wheel instead.

Don,
Six bearings in all (one on each end of: input, layshaft and output), flange seal, output shaft seal, case gasket and a few o-rings plus several shift mechanism plastic bits and the return spring in for the shift mechanism. A great source of parts and tools is Dan at http://www.cycleworks.net Dan also carries an instructional video with numerous great tips. I also picked up an infrared thermometer that allowed me to bring the case up to 150 degrees F for dis-assembly and assembly. A key tool that Dan stocks are two parallel bars and the shim measuring plate. And, the flange removal tool is a must to get that monster loose. My favorite description of rebuilding the airhead transmission was that you require the skills of hand to hand combat plus neurosurgeon. There are a couple of bolts that are VERY tight and then setting the shaft end-play is quite delicate.

If you discover broken dogs or broken gears, please note there are a number of different transmissions with different helical gears (7.5 degrees vs. 15 degrees) as well as different sizes and number of teeth.

DaveM
1975 R90S
2000 R1100RT

Well, believe it or not, I'm resurrecting this thread. I have put it off and put it off, but now have 3 transmissions apart, and on my bench. I have nearly all the replacement parts (bearings, seals, gaskets) on hand.

One remaining question is which springs to replace on the shift mechanism. It looks like there are 3 springs, but I think the last time I did this I only replaced the pawl spring.

Advice? Part numbers? Recommended supplier?

Thanks,

Don

The camp is generally split on replacing any of the springs in the shift mechanism.
Due to reported premature breakages of new springs, some advise to let sleeping dogs lie.

I left the original springs in my recent tranny rebuild.

Maybe ask on adv airheads as well, where there is a lot more experience with said springs.

Hey Don, do you want a burnt out gearbox to experiment with?
Yours for the price of shipping (what the hell, I'll split the cost with you!). I'm not even sure if it is still serviceable. (Google "rob needs a new brain")
The drain plug fell out on me (or something) and I ran it in 5th gear for a while until I got off the interstate. When I went to downshift I knew something was not right...

It could be a good ribbed case, some of the gears might still be good, but mostly I am just looking for someone to perform an autopsy with pictures.