About breams

Baby Boomer generation. Integrator of the disconnected. Engineer, BMW motorcycle addict and Iron Butt enthusiast.

33 BMW 1983 R80ST Rebuild Rear Drive

I suspect the final drive seals are leaking, and this bike has been sitting for about 25 years. So I am rebuilding and refinishing the rear drive. I have never rebuilt a rear drive before and I understand this requires some special tools and also correct shimming of the pinion and crown gear; aka, ring gear. So I asked Matt Iles, owner of Iles Motorsports, if I could watch him do this work, and he agreed. I have Matt replace all the seals and bearings in the final drive so it will be good for another 40 years and 100,000 miles. 🙂 That way I get an education about how this is done so I can decide if I am capable of doing this work in the future. Any mistakes in this documentation are on me, not Matt.

Here is the link to my documentation of Matt’s work.

Here are some before and after pictures.

Original Rear Drive Before Removal From Swing Arm

Original Rear Drive Before Removal From Swing Arm

Rear Drive Case Before Vapor Blasting

Rear Drive Case Before Vapor Blasting

Vapor Blasted, Rebuilt Rear Drive

Vapor Blasted, Rebuilt Rear Drive

Vapor Blasted, Rebuilt Rear Drive

Vapor Blasted, Rebuilt Rear Drive

Vapor Blasted, Rebuilt Rear Drive

Vapor Blasted, Rebuilt Rear Drive

 

1983 BMW R80ST Install Transmission

After removing the transmission, I disassembled it, had the case and rear cover vapor blasted, rebuilt the shift cam assembly, input, intermediate and output shafts and reassembled the transmission. You can read about that work here.

So, now I’m ready to install it. I also install the clutch throw-out lever assembly, foot shifter assembly, clutch cable and speedometer cable. Here is a link to the documentation about installing the 1983 R80ST transmission and a YouTube video.

VIDEO: 1983 BMW R80ST Install Transmission

Here are the before and after pictures of the transmission.

Transmission Condition As I Found It

Transmission Condition As I Found It

Transmission Condition As I Found It

Transmission Condition As I Found It

Transmission Installed

Transmission Installed

Transmission Installed

Transmission Installed

 

1983 BMW R80ST Disassemble, Rebuild, Assemble Transmission

The 1983 R80ST transmission is the same as the 1983 R100RS transmission that I rebuilt previously. So in this document, I provide links to the 1983 R100RS documents showing how I disassemble, rebuild and reassemble the transmission.  I will provide pictures and details about what I find when I open up the R80ST transmission and will document any work I have to do on the R80ST that is different from the work I did on the R100RS.

I have the transmission cases vapor blasted by Colorado Vapor Blasting in Arvada, CO who is generously providing a discount to me in support of my goal of a charity auction of this R80ST to support the Motorcycle Relief Project.

Here is the link to the documentation for the transmission disassembly, rebuild and assembly including pictures of the 1983 R80ST transmission.

Here are pictures of the rebuilt transmission.

Transmission Serial Number-Z078854

Transmission Serial Number-Z078854

Transmission Assembled-Red Tape On Fill Plug Means I Haven't Put Gear Lube In The Transmission Yet

Transmission Assembled-Red Tape On Fill Plug Means I Haven’t Put Gear Lube In The Transmission Yet

Transmission Assembled-Rear

Transmission Assembled-Rear

Transmission Assembled-Bottom

Transmission Assembled-Bottom

Transmission Assembled-Front

Transmission Assembled-Front

 

1983 BMW R80ST Install Front Brake

The 1983 R80ST has a single front disk brake. The brake disk is mounted on the right side of the front wheel. This bike did not have the front disk, so I got a new one. I rebuilt the front brake caliper and you can see how I do that here.

Here is the description of how install the front brake and a summary YouTube video of how I do this work.

VIDEO: 1983 BMW R80ST Install Front Brake

1983 BMW R80ST Rebuild Front Brake Caliper

The 1983 R80ST has a single front disk brake on the right side of the front wheel. It uses a Brembo caliper connected to a master cylinder and fluid reservoir built into the right handlebar control unit.  I repainted the caliper using black caliper paint.

Here is what the caliper looked like when I got the bike removed it from the bike.

As Found: Front Brembo Disk Brake Caliper And Missing Brake Rotor

As Found: Front Brembo Disk Brake Caliper And Missing Brake Rotor

Brembo Front Brake Caliper With Crusty Looking Brake Pads

Brembo Front Brake Caliper With Crusty Looking Brake Pads

And this is how it looks after repainting and rebuilding.

Brembo Front Caliper After Rebuilding

Brembo Front Caliper After Rebuilding

Brembo Front Caliper After Rebuilding

Brembo Front Caliper After Rebuilding

Brembo Front Caliper After Rebuilding

Brembo Front Caliper After Rebuilding

This shows how I do the work.

Here is a short video summarizing the procedure. It is a mix of video from the 1983 R100RS and 1983 R80ST.

VIDEO: 1983 BMW R80ST Rebuild Front Brake Caliper