Now the gearbox is stripped, leaving just a few bearings and seals to be removed, which I'll tackle next time. So far so good. Here's a picture of what I've dismantled so far (as described above, but also includes a few odds and ends such as the neutral switch, drain plug etc).
Gearbox learning curve Part 1
- Thread starter Wanderer
- Start date
B Murr
Registered user
A video of all this work would be interesting and I'm sure a few copies would be sold here but I guess it's the last thing you want to do when you are doing this sort of work unless you have an assistant.
There is one available, though it's not as step by step. I'm finding it very useful though and would thoroughly recommend it. If interested search on Ed Korn. He's in the US and also makes certain tools for airheads.
Interesting learning point. In March 1982 BMW changed the tooth profile on the input shaft and the fifth gear cogs on the intermediate and output shafts. There's more detail on Largiader's excellent site here (http://www.largiader.com/tech/airtrans/).
Below is a picture comparing the pre and post March 1982 shafts. Using this information, I can determine that the input shaft in my guinea pig gearbox is a post March 1982 shaft with a 17.5 degree tooth profile (as shown in the second picture below).
Below is a picture comparing the pre and post March 1982 shafts. Using this information, I can determine that the input shaft in my guinea pig gearbox is a post March 1982 shaft with a 17.5 degree tooth profile (as shown in the second picture below).
Attachments
Grand job
Will, you are doing a grand job in posting this thread. Repairing gearboxes has filled me with worries in the past,
having seen your pictures and comments I feel like maybe I could have a go at repairing one of mine. Out of interest, what if anything was wrong with the one you are taking apart?
Many thanks and keep up the good work
Nick
Will, you are doing a grand job in posting this thread. Repairing gearboxes has filled me with worries in the past,
having seen your pictures and comments I feel like maybe I could have a go at repairing one of mine. Out of interest, what if anything was wrong with the one you are taking apart?Many thanks and keep up the good work
Nick
Will, you are doing a grand job in posting this thread. Repairing gearboxes has filled me with worries in the past,
Many thanks and keep up the good work
Nick
Hi Nick
Nothing wrong with my guinea pig gearbox. Bought from a fellow tosser of this parish (Big Jets
) for a very reasonable sum. In a shocking condition (oil was 50:50 oil and mud!) but Big Jets had bought a complete engine as an intended project and never gotten round to it. I simply wanted a cheap gearbox to use as a learning project.My reason for doing so stems from my R90. I had a problem with that the other year. I started the strip down but couldn't get the intermediate and output shafts out (wasn't using enough heat). So for the first time I had to outsource help (thanks to Southport Superbikes). Nothing wrong with this, but it's all been a big and enjoyable learning experiment thus far. It was simply my frustration at this that led to this project. I'd like to know: how exactly does a gearbox work, how to remove stuck output shafts, how to take bearings off shafts, and put them back on again, what are the differences between airhead boxes, and why were the differences introduced, etc etc etc? I love (a) knowing how things work and (b) being able to do things myself. After the gearbox will be a final drive unit, then an engine, then welding, the list goes on! I know I'll never be a specialist, and will always turn to an expert for help, but I love learning.
Sorry for the long reply
(RIP) Bin Ridin
Registered user
Bravo Will, most interesting!
Thanks!
Thanks!
Just a reminder for anyone thats never removed the end cover on a gearbox before - remove the speedo drive out of the case before attempting to pull the end cover off.
If your wondering, here's a how to replace the detent spring, the most common problem on airhead boxes [URL="http://www.ukgser.com/forums/showthread.php?t=35961&highlight=steptoe"]Detent spring[/URL]....
Good pictorial Will
Good pictorial Will
Thanks Steppers
thumb2), means a very lot coming from someone with your knowledge of these matters 
gearbox
Very good, Will, thanks.
Very good, Will, thanks.
B Murr
Registered user
Crikey -$138 plus postage for the three videos required to cover the gearbox and engine. Maybe I'll spot some back-up copies in someones carboot sale
