About breams

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

1983 BMW R100RS Rebuild Master Cylinders & Brembo Calipers

This bike has a front master cylinder that is integrated into the Magura throttle assembly and a rear Brembo master cylinder. All three calipers are Brembo F-08 series with dual 38 mm pistons.  I disassembled both master cylinders and inspected them. I repainted and rebuilt the rear master cylinder using a Brembo rebuild kit. Unfortunately, I found the front Magura master cylinder bore and internals were badly rusted and pitted, so I had to replace the front master cylinder rather than rebuild it. Even though I didn’t have to rebuild the front master cylinder, I show how you rebuild it and the rear master cylinder in this document.

I also put together two short videos showing the work I did on the front and the rear master cylinders.

1983 R100RS Disassemble & Inspect Front Master Cylinder

1983 R100RS Disassemble, Inspect & Rebuild Rear Master Cylinder

I removed the brake calipers when I removed the brake system and you can see how to remove the calipers here:

I disassembled all three calipers, inspected them and found they were not corroded or pitted so I repainted and rebuilt them using a Brembo caliper rebuild kit. The same kit is used on all three calipers. You can see how I did that work here:

I also put together a video about how I rebuilt the calipers.

1983 R100RS Disassemble, Inspect & Rebuild Brembo Brake Calipers

1983 BMW R100RS Repair Broken Side Cover Tabs on Sub-Frame

For some reason both tabs that help hold the left side cover on are broken off on the Sub-frame.  I fabricated new ones out of some scrap steel lawn edging and had my son weld them to the sub-frame.

If you have to make this repair, here is how I made them.

Some pictures follow.

Sub-Frame Leg With Original Brackets

Right Sub-Frame Leg With Original Brackets

Sub-Frame Leg With Both Brackets Broken Off

Left Sub-Frame Leg With Both Brackets Broken Off

12 mm Socket For Finishing Round End Radius

12 mm Socket For Finishing Round End Radius

Use Drift in Vice To Form Radius At End of Bracket

Use Drift in Vice To Form Radius At End of Bracket

Brackets Ready For Welding

Brackets Ready For Welding

New Tabs-Just Like The Original

New Tabs Look Just Like The Original

New Tabs-Just Like The Original

New Tabs Look Just Like The Original

 

1983 BMW R100RS Remove Swing Arm Bearings

I’m going to powder coat the swing arm, and the bike has 83,000+ miles on it. So I am removing the swing arm bearings and will replace them.

BMW used two different style bearings on the airhead swing arm: an unsealed 30203 bearing that was changed part way through the 1981 model year (01/1981) to a sealed bearing, FAG 540619. Changes in the swing arm bearing assemble were made at the start of the 1981 model year (09/1980) when the pivot pin was shortened and the dust cap changed to accommodate the 30203 bearing with the shorter pivot pin. Then in January 1981, the sealed bearing was added with it’s included dust cap.

I’ve removed the 30203 bearings before using the tool from Cycle Works.

Cycle Works Bearing Puller Kit

Cycle Works Bearing Puller Kit

But it won’t fit inside the captive sleeve of the sealed bearing. And I can’t remove the inner race without a puller as it is captive due to the sealed bearing design. So I bought a set of blind bearing pullers for less than $60.00.

This kit has a slide hammer and a set of puller legs when more force–that will be required for the outer race extraction–is needed. There are various size expanding sleeves that cover a wide range of bearing diameters, so I bought it.

Less Than $60.00 Blind Bearing Puller Set

Less Than $60.00 Blind Bearing Puller Set

I made a collar so I could use the blind puller to remove the outer race. It cost me $7.00 in parts. I used it to remove on of the outer races and it worked nicely. So, if you have a set of blind bearing pullers, or buy a set like I did, you can remove the outer race by making your own collar.

Washer Rests On Edge Of Tube That Holds The Bearing

Washer Rests On Edge Of Tube That Holds The Bearing

Blind Bearing Puller With Jaws Ready To Extract Outer Race

Blind Bearing Puller With Jaws Ready To Extract Outer Race

Sealed Bearing Disassembled

FAG Sealed Bearing Disassembled During Removal

Here is a link to the documentation I wrote about how I did this work.

I also made a short video and posted it to my YouTube channel.

1983 BMW R100RS Remove Drive Shaft

I’m going to powder coat the swing arm so I need to remove the drive shaft. BMW used two different drive shaft designs on the airheads changing the design in the 1981 model year. This 1983 RS has the second design drive shaft.

Pre-1981 Drive Shaft and Swing Arm

Pre-1981 Drive Shaft Components and Swing Arm

Pre-1981 Driveshaft With Tapered End That Shrink Fits Into Bell Coupling

Pre-1981 Drive Shaft With Tapered End That Shrink Fits Into Bell Coupling

Drive Shaft Assembly Components

1981+ Drive Shaft Assembly Components

1981+ Drive Shaft Torsional Shock Absorption Assembly

1981+ Drive Shaft Torsional Shock Absorption Assembly

Cycle Works makes tools to remove the drive shaft. So they have two different tools.

Cycle Works Driveshaft Removal Tool 1955-1980

Pre-1981 Cycle Works Drive Shaft Bell Housing Removal Tool

Pre-1981 Cycle Works Drive Shaft Bell Housing Removal Tool

Here is a link to the description of this tool.

Cycle Works Driveshaft Spring Compressor Tool 1981+

This the tool used to compress the drive shaft spring so I can remove the snap ring that secures large yoke with the bell coupling from the drive shaft.

1981+ Cycle Works Drive Shaft Removal Tool Components

1981+ Cycle Works Drive Shaft Removal Tool Components

Here is a link to the tool description.

I documented how I did this work here:

And, I made a video showing assembly of the Cycle Works drive shaft spring compressor tool and how I used it to remove the drive shaft.

1983 BMW R100RS Remove Valves and Inspect

I’m going to have the heads on this project dual-plugged. Before I sent them to Randy Long who does this work, and more, I did an inspection of the valves to see what I could learn. I documented this work here:

It includes this short video.

VIDEO: 1983 BMW R100RS Remove Valves and Inspect

Randy Long is an excellent resource if you need work done on your heads, valves or seats. He doesn’t have a web site, so here is his contact information:

Randy Long
Long’s Mechanical Services
74 Risbon Rd
Honey Brook, PA 19344-1754
(610) 286-5870