1983 BMW R100RS Rebuild Transmission

This is the second time I have worked on rebuilding an airhead transmission. That should make it clear that I am an amateur, not a professional, when it comes to doing this work. I would not attempt to rebuild a transmission unless I have access to experienced, long time, airhead mechanics. I’m very fortunate to have access to three of them. And, I plan to continue rebuilding transmissions on my own projects, so the considerable investment in tools will get amortized over the future projects.

NOTE:
I would not recommend that you rebuild your transmission unless you have completed multiple bike rebuilds, have invested in precision measurement tools and specialized transmission tools, and expect to rebuild multiple transmissions. The cost and risk are too high if you just plan to do one transmission. I would recommend you have your transmission rebuilt by a reputable builder such as Tom Cutter at Rubber Chicken Racing Garage in Pennsylvania, Matt Parkhouse ([email protected]in Colorado, Bob Clement at Bob’s Motorwerks ([email protected]) in Montana, and Bud Proven at The Nickwackett Garage in Vermont.

This transmission has over 83,000 miles on it. That said, it was in good condition when I had the parts inspected by an airhead mechanic. So that’s a good thing.

I wrote five documents showing how I do the work.

And, I shot five YouTube videos summarizing the work in each document.

VIDEO: 1983 R100RS Disassemble The Transmission

VIDEO: 1983 BMW R100RS Rebuild Transmission Shift Cam Assembly

VIDEO: 1983 BMW R100RS Rebuild Transmission Input & Intermediate Shafts

VIDEO: 1983 R100RS Rebuild Transmission Output Shaft

VIDEO: 1983 R100RS Assemble Transmission

This is what I started with:

Transmission Before

Transmission Before

Transmission Before

Transmission Before

Transmission Before

Transmission Before

Transmission Before

Transmission Before

And this is what things looked like during disassembly.

What's Inside The Transmission

What’s Inside The Transmission

Shift Cam Assembly Parts

Shift Cam Assembly Parts

Input Shaft Parts

Input Shaft Parts

Output Shaft Parts

Output Shaft Parts

Intermediate Shaft Front Bearing Removed

Intermediate Shaft Front Bearing Removed

And this is the final result.

All Done-Red Tape Means "Needs Attention" As In Gear Lube

All Done-Red Tape Means “Needs Attention” As In Gear Lube

All Done

All Done

1983 BMW R100RS/RT Routing Main Wiring Harness

I show how I route the main wiring harness after I installed the headlight shell.  Previously I replaced the main harness with one from Euro MotoElectrics.

Here is the document showing the details and a short video.

VIDEO: 1983 BMW R100RS Routing Main Wiring Harness

Below are a couple of the pictures from the write-up.

Main Harness Cable Exits Bottom Of Headlight Shell

Main Harness Cable Exits Bottom Of Headlight Shell

Main Harness Goes Under Lower Triple Clamp (aka Yoke)

Main Harness Goes Under Lower Triple Clamp (aka Yoke)

Main Harness Goes Between Frame Down Tubes

Main Harness Goes Between Frame Down Tubes

Main Harness Goes Between Spine Tube and Reinforcing Tube

Main Harness Goes Between Spine Tube and Reinforcing Tube

Front Brake Light Switch Sub-Harness Plug (GREEN-Red, GREEN-Black) & Clutch Switch Sub-Harness Plug (BROWN-Yellow)

Front Brake Light Switch Sub-Harness Plug (GREENRed, GREEN-Black) & Clutch Switch Sub-Harness Plug (BROWNYellow and BROWN )

Main Wiring Harness Coil Power Terminal (GREEN-Blue) Goes On Same Terminal As EME Optical-Electronic Ignition Control Unit Power Wire (RED)

Main Wiring Harness Coil Power Terminal (GREENBlue) Goes On Same Terminal As EME Optical-Electronic Ignition Control Unit Power Wire (RED)

 

1983 BMW R100RS Install Seat and Fork Locks

I completed installation of the fork and seat locks. I show the assembly of the seat latch mechanism and installation and also made a short video showing how I do the work.

VIDEO: 1983 BMW R100RS Install Fork and Seat Locks

Here is a link showing how I removed the locks.

1983 BMW R100RS Install Sub-Frame, Gazi Shocks and Wheels

I completed installing the rear end of the motorcycle. The fenders and rear lights will come in another post. You can read about how I did that work in these chapters of the “Assembly From The Frame Up” document:

Sub-Frame and Rear Shocks Mounted

Sub-Frame and Rear Shocks Mounted

Wheels Installed

Wheels Installed

It’s beginning to look like a motorcycle again 🙂

 

1983 BMW R100RS/RT Assembly From The Frame Up Page

I put together a page showing the order in which I am assembling the bike on this project. I will add to it as I go. In most of this document I link to other pages I posted, but for some work that is not particularly detailed, I show how to do the work in the Assembly page.

There is also a companion document that shows how I disassembled the bike.

I also have documented the project work on a Project Index page that includes a list of every document I published for this project organized by parts fiche major component number.

Here is a link to the YouTube videos I’ve posted about this project on my channel.

Lastly, there is a complete archive of all the pictures on Flickr.