51 BMW 1983 R100RS Repair, Refinish, Paint

This page consolidates the work I do to repair, refinish and paint parts during the rebuild of the 1983 R100RS into an RT model.  Let me explain how I use the terms.

  • Repair: Fix something that is broken; not the same as parts replacement.
  • Refinish: Restore the finish, typically of aluminum castings, to factory condition
  • Paint: Strip and paint parts often to match the factory paint. This does not cover professional painting and powder coating.

Some sections of this document have links to a separate document, or section of a document, I published. Other sections contain original material.

Resources

I published a document summarizing various techniques, products and tools I use to refinish parts on my projects. You can review this material here:

Robert Fleischer, aka, “Snowbum” published material on care, repair and refinishing techniques, materials, etc.

Brake Calipers Painting

I show how I repainted the front and rear brake calipers in a document about how I rebuild them. You will find information about refinishing them here.

Before

Here is what I started with.

BEFORE: Brembo Front Brake Caliper

BEFORE: Brembo Front Brake Caliper

BEFORE: Brembo Rear Brake Caliper

BEFORE: Brembo Rear Brake Caliper

After

And here is where I ended up.

AFTER: Repainted & Rebuilt

AFTER: Repainted & Rebuilt

Rear Brake Plate Refinish & Rear Brake Stay Painting

The rear brake plate and stay were is rough shape.

Grungy & Corroded Rear Brake Stay and Brake Plate

Grungy & Corroded Rear Brake Stay and Brake Plate

Grungy & Corroded Rear Brake Stay and Brake Plate

Grungy & Corroded Rear Brake Stay and Brake Plate

I cleaned the brake plate in the parts washer and used a brass wire brush to get as much of the caked on brake fluid and dirt as I can. Then I used my bead blaster set for 40-50 psi at the nozzle to refinish the brake plate.

Refinished Rear Brake Plate

Refinished Rear Brake Plate

Refinished Rear Brake Plate

Refinished Rear Brake Plate

I bead blasted the rear brake stay to remove all the rust. Then I primed it with etching primer and painted it with engine block paint which closely matches the original zinc plating used on the stay.

Self-Etching Primer

Self-Etching Primer

Engine Block Paint

Engine Block Paint

Painted Rear Brake Stay Looks New Again

Painted Rear Brake Stay Looks New Again

Carburetors Refinish

The document I published in the Resources section above includes information about how to refurbish the carburetors so the finish looks new again.

I show how to repaint the white BING lettering used on the carburetors on this bike in a separate document.

Before

This is what I started with.

BEFORE: Left Carburetor Top

BEFORE: Left Carburetor Top

BEFORE: Left Carburetor Detail

BEFORE: Left Carburetor Detail

BEFORE: Left Carburetor Choke Side

BEFORE: Left Carburetor Choke Side

BEFORE: Right Carburetor Top

BEFORE: Right Carburetor Top

BEFORE: Right Carburetor Side

BEFORE: Right Carburetor Side

After

And here is what I ended up with.

AFTER: Choke Side of Carburetor

AFTER: Choke Side of Carburetor

AFTER: Top Side of Carburetor

AFTER: Top Side of Carburetor

AFTER: Left Carburetor

AFTER: Left Carburetor

Engine Block Refinish

The document I published in the Resources section above includes information about how I refinish rough, cast aluminum like the engine block.

Before

Here is what I started with.

BEFORE: Lower Engine Block-Oil Well Blow Out

BEFORE: Lower Engine Block-Oil Well Blow Out

BEFORE: Engine Block

BEFORE: Engine Block

BEFORE: Oil Pan Rear Leaking

BEFORE: Oil Pan Rear Leaking

After

And, here is what I ended up with.

Refinished Engine Block

Refinished Engine Block

Refinished Engine Block

Refinished Engine Block

Refinished Engine Block

Refinished Engine Block

Refinished Oil Pan

Refinished Oil Pan

Refinished Oil Pan

Refinished Oil Pan

Refinished Oil Pan

Refinished Oil Pan

Engine Covers

I cleaned and repainted the top and inner timing engine covers. I cleaned and polished the front engine cover to remove as much of the aluminum corrosion as I could.

Inner Timing Cover Painting

I used engine cleaner to remove all the old oil and grunge and a wire brush to remove the stubborn deposits. Then I washed it my parts washer. There were areas of failed paint and I used my bench top blast cabinet to remove the loose paint. I do this in the driveway so I don’t get any of the glass inside my shop.

BEFORE-Inner Timing Cover

BEFORE-Inner Timing Cover

BEFORE-Inner Timing Cover

BEFORE-Inner Timing Cover

I taped off the mating surface to keep paint off it.

Masked Off Inner Timing Cover Mating Surfaces

Masked Off Inner Timing Cover Mating Surfaces

I spot painted primer on the bare metal and then painted it with gloss black caliper paint.

Inner Timing Cover Painted with Gloss Black Caliper Paint

Inner Timing Cover Painted with Gloss Black Caliper Paint

After the paint was dry, I used a paint scraper to remove the paint from the fins to expose the aluminum.

Clean Paint Of Aluminum Fins Using Paint Scraper

Clean Paint Of Aluminum Fins Using Paint Scraper

Finished Inner Timing Cover

Finished Inner Timing Cover

Finished Inner Timing Cover

Finished Inner Timing Cover

Then I backed it in the oven at 200 F for an hour to harden the paint.

Top Engine Cover Painting

I painted the top engine cover using the same process to paint the inner timing cover.

Before

BEFORE: Front Engine Cover

BEFORE: Front Engine Cover

BEFORE: Front Engine Cover

BEFORE: Front Engine Cover

After

Top Engine Cover Painted

Top Engine Cover Painted

Final Top Engine Cover

Final Top Engine Cover

Front Engine Cover Refinish

I use the same procedure on the front engine cover that I use to refinish the rear drive, but with more aggressive cleaning due to the degree of corrosion.

I use 800 grit wet/dry paper to clean up the more heavily corroded areas on the cover. Then I use a brass brush with AutoSol aluminum cleaner followed by “0000” steel wool and the aluminum cleaner and then toothbrush with the alumium cleaner. This eliminated scratches from the sand paper, but there is still a lot of corrosion on the front cover.

Front Engine Cover with Corrosion

Front Engine Cover with Corrosion

AutoSol Aluminum Cleaner

AutoSol Aluminum Cleaner

Brass Brush Applied Cleaner

Brass Brush Applied Cleaner

Steel Wool Applied Aluminum Cleaner

Steel Wool Applied Aluminum Cleaner

AutoSol Metal Polish

AutoSol Metal Polish

Toothbrush Applied Polish

Toothbrush Applied Polish

Toothbrush Applied Aluminum Polish

Toothbrush Applied Aluminum Polish

(L)-Before Polishing; (R)-After Polishing

(L)-Before Polishing; (R)-After Polishing-Still Has Corrosion Spots (Look Toward Bottom Right)

So, elbow grease, cleaners, abrasives and polish do did not remove the corrosion as it’s too deep. So I get out the big gun; my Harbor Freight tabletop blasting cabinet. I bead blast the cover to remove the corrosion spots.

NOTE:
I NEVER use this blaster inside the shop. As you can see on the top of the cabinet, fine glass dust goes everywhere and I DO NOT want any of that inside the shop where it can contaminate all the other parts.

Getting Out The Big Gun

Getting Out The Big Gun

I blast a small section at a time, but at a reduced pressure of about 40-50 PSI so the glass beads don’t erode the soft aluminum too much, but have just enough velocity to blast off the corrosion spots.

I inspect each section after the initial bead blasting for remaining spots and I use a Sharpie to mark any sections with some corrosion and blast them again. I continue this way until I have all the corrosion removed from the cover. It takes me over 2 hours to complete this work due to the small compressor I have.

Marking Sections with Corrosion Spots For Another Blasting

Marking Sections with Corrosion Spots For Another Blasting

Front Engine Cover After Bear Blasting with Corrosion Spots Removed

Front Engine Cover After Bear Blasting with Corrosion Spots Removed

After I bead blast the front cover, I clean it again with the AutoSol aluminum cleaner and a toothbrush. Then I lightly polish it with a blue shop towel using a small amount of AutoSol metal polish on small sections until I the cover has uniform lightly polished sheen. Finally I use  brake cleaner on a clean blue shop towel to remove the remaining aluminum oxide residue left behind by the metal polish.

Brake Cleaner

Brake Cleaner

Aluminum Oxide Removed with Brake Cleaner

Aluminum Oxide Removed with Brake Cleaner

This leaves a light polished luster that looks close to the original patina of the aluminum cover. The cover closely matches the refinished engine block and vapor blasted cylinders.

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Refinished Front Engine Cover

Front Fork Lower Slider Repaint

I painted the lower fork sliders as there was a fair amount of rock chips. I sanded the lower sliders with 400 wet/dry paper to remove any loose paint and the rough up the surface. I used matte engine paint so they would only have a minimal amount of gloss to compliment the matte white wheels.

Fork Lower Slider Dings

Fork Lower Slider Dings

Fork Lower Slider Dings

Fork Lower Slider Dings

Fork Lower Slider Dings

Fork Lower Slider Dings

Fork Lower Slider Dings

Fork Lower Slider Dings

Sand Fork Lower Sliders With 400 Grit Wet/Dry Paper

Sand Fork Lower Sliders With 400 Grit Wet/Dry Paper

Mask Off Reflector and Top Of Slider Where Dust Cap Fits

Mask Off Reflector and Top Of Slider Where Dust Cap Fi

Tape Masking Of Lower Slider Face with Bolt in Drain Hole To Hang It For Painting

Tape Masking Of Lower Slider Face with Bolt in Drain Hole To Hang It For Painting

Repainted Lower Fork Sliders

Repainted Lower Fork Sliders

Pannier Repair

I repaired a number of cracks and large holes in the panniers. You can read about how I do that here.

Before

Holes in Bottom

Holes in Bottom

Small Hole and Cracks

Small Hole and Cracks

Lock Crack

Lock Crack

After

Hole Filled In

Hole Filled In

Finished Crack Repair

Finished Crack Repair

Crushed Corner Crack Repair

Crushed Corner Crack Repair

Crushed Corner Final Repair

Crushed Corner Final Repair

Rear Drive Refinish

The rear drive was painted black by a previous owner and was pealing. I used Aircraft paint stripper to get the paint off.

Rear Drive Was Painted Black-Looking Beat Up

Rear Drive Was Painted Black-Looking Beat Up

Parts After First Application of Aircraft Paint Stripper

Parts After First Application of Aircraft Paint Stripper

After Paint Removed Some Corrosion Visible

After Paint Removed Some Corrosion Visible

Where there were some areas of discoloration and bits of old paint the stripper didn’t remove, I used “0000” steel wool, Then I used the metal polish with the tooth brush again to remove any bits of steel wool left behind.

Bits of Paint I Remove with Steel Wool

Bits of Paint I Remove with Steel Wool

I use AutoSol aluminum cleaner and a toothbrush to clean the aluminum. Then I used AutoSol metal polish to get the patina back putting it on a toothbrush so I could do a better job of polishing in the pores.

AutoSol Aluminum Cleaner

AutoSol Aluminum Cleaner

Toothbrush with Aluminum Cleaner Deep Cleans Casting Pores

Toothbrush with Aluminum Cleaner Deep Cleans Casting Pores

Upper-Deep Cleaned, Lower Not Deep Cleaned

Upper-Deep Cleaned, Lower Not Deep Cleaned

Still Needs Cleaning

Still Needs Cleaning

AutoSol Metal Polish

AutoSol Metal Polish

Apply Metal Polish to Tooth Brush

Apply Metal Polish to Tooth Brush

Deep Polishing with Toothbrush

Deep Polishing with Toothbrush

Finally, I use a brass brush to buff up the surface. The brass brush is less abrasive than a steel brush and seems to bring the luster out of the aluminum pores.

Brass Brush

Brass Brush

Brass Brush Improves Patina

Brass Brush Improves Patina

Before

Rear Drive Was Painted Black

Rear Drive Was Painted Black

Rear Drive Was Painted Black

Rear Drive Was Painted Black

Rear Drive Was Painted Black

Rear Drive Was Painted Black

After

Refinished Rear Drive

Refinished Rear Drive

Refinished Rear Drive

Refinished Rear Drive

Refinished Rear Drive

Refinished Rear Drive

Sub-frame Repair

The battery panel tabs were broken off on one side of the sub-frame. I show how I fabricated new ones and had them welded on here.

I powder coated the sub-frame to match the main frame and swing arm.

Before

Brackets Broken Off

New Tabs-Just Like The Original

After

Sub-frame After Powder Coat

Sub-frame After Powder Coat

Sub-frame After Powder Coat

Sub-frame After Powder Coat

Sub-frame After Powder Coat

Sub-frame After Powder Coat

Triple Clamp Refinishing

The aluminum was dirty and grease caked but not corroded. I used the parts washer to clean the grunge off.

Looks Like Wheel Bearing Grease Was Used and Melted Making A Mess

Looks Like Wheel Bearing Grease Was Used and Melted Making A Mess

Looks Like Wheel Bearing Grease Was Used and Melted Making A Mess

Looks Like Wheel Bearing Grease Was Used and Melted Making A Mess

Bottom of Lower Triple Clamp Where Steering Damper Housing Mounts

Bottom of Lower Triple Clamp Where Steering Damper Housing Mounts

I followed up with AutoSol aluminum cleaner and a toothbrush. Next I used “0000” steel wool with the aluminum cleaner to remove the surface oxidation. I finished up with AutoSol metal polish to bring back the shine in the polished aluminum.

Step 1: AutoSol Aluminum Cleaner with Toothbrush

Step 1: AutoSol Aluminum Cleaner with Toothbrush

Before Using Aluminum Cleaner with "0000" Steel Wool

Before Using Aluminum Cleaner with “0000” Steel Wool

Step 2: "0000" Steel Wool with Aluminum Cleaner

Step 2: “0000” Steel Wool with Aluminum Cleaner

After Aluminum Cleaner with "0000" Steel Wool

After Aluminum Cleaner with “0000” Steel Wool

Step 3: Ready To Polish

Step 3: Ready To Polish

Final Product

Final Product

Final Product

Final Product

Valve Cover Painting

I like to use caliper paint to refresh the valve covers. I stripped the old paint off with Aircraft paint remover.

Parts After First Application of Aircraft Paint Stripper

Parts After First Application of Aircraft Paint Stripper

These covers had some scrapes in them. I use 220 grit wet/dry paper to polish out as much of the scrape as I can.

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

Valve Cover Condition

When I finish painting them, I wait overnight.

Valve Covers Drying

Valve Covers Drying

Valve Covers Painted

Valve Covers Painted

I use a paint scraper with a razor blade to remove the paint from the horizontal ridges on the covers. Then I use a block of wood with 600 grit wet/dry paper and lightly sand the ridges to get them nice and shiny.

Making Fins Shine

Making Fins Shine

Then I bake the covers at 200 F in the oven for an hour to help harden the paint

Bake at 200 F For 1 Hour

Bake at 200 F For 1 Hour

Here is how they look mounted on the heads.

Refreshed Valve Cover

Refreshed Valve Cover

Refreshed Valve Cover

Refreshed Valve Cover

Transmission Refinish & Cover Repair

So, what did I start with? It looked like this transmission had more than one leaking seal and had not been cleaned in a long time.

Transmission Before A Bath

Transmission Before A Bath

Transmission Before A Bath

Transmission Before A Bath

Transmission Before A Bath

Transmission Before A Bath

Transmission Before A Bath

Transmission Before A Bath

So, time for a bath with engine cleaner followed by kerosene applied with a paint brush, scrubbing with stiff bristle brushes and then a hot water rinse in the sink.

Time For A Bath

Time For A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

Transmission After A Bath

I bead blasted the transmission housing and rear cover at low pressure (about 40 psi). But before I did that, I thoroughly cleaned the inside of the case and cover with engine degreaser followed by hot soap and water rinses to remove any gear lube inside them.

After blasting, I cleaned them three times with a tooth brush and stiff nylon bushes in hot soapy water to remove any trace of glass dust. After each washing, I blasted the inside of the case with compressed air and wiped inside the crevices of the corners of the reinforcing webs inside the case and cover with Q-tips wet with carb cleaner to remove any glass grit that might be caught there. As a final check, I rubbed my fingers over the inside of the case to see if I can fell any grit. There were some spots that felt gritty and I cleaned that area again with a blue shop towel or Q-tip with carb cleaner to remove the grit until I couldn’t feel it. Then I washed the case one more time and repeated the finger test. This time I couldn’t feel any grit.

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Case

Refinished Transmission Rear Cover

Refinished Transmission Rear Cover

Repair Void In Rear Cover Mating Surface

After disassembling the transmission I noticed a casting void in the mating surface where the gasket goes.

Rear Cover Has A Casting Void In Mating Surface

Rear Cover Has A Casting Void In Mating Surface

I fill that with JB Weld. I clean the void with engine degreaser, alcohol and then brake cleaner to get all the gear lube out of the pores of the aluminum. I fill the void and level it with a box cutter blade. After it dries for 24 hours,  I carefully file and then lightly sand with 600 wet/dry paper and a wood block to get the repair flat with the mating surface being careful not to round the mating surface. This maybe one reason the transmission was so grungy.

Void Cleaned with Brake Cleaner and Ready For Repair

Void Cleaned with Brake Cleaner and Ready For Repair

Use Box Cutter Blade To Level Wet JB Weld And Remove Excess

Use Box Cutter Blade To Level Wet JB Weld And Remove Excess

JB Weld Repair To Void In Gasket Mating Surface After Drying

JB Weld Repair To Void In Gasket Mating Surface After Drying

Handlebar Perch Painting

I had to replace the right side perch and front brake master cylinder due to damage. The original left side perch and lever are in need of painting, so I stripped them using my bead blasting cabinet and painted them using a matte black caliper paint.

Left Handlebar Perch & Lever Need Painting

Left Handlebar Perch & Lever Need Painting

Left Handlebar Perch & Lever Need Painting

Left Handlebar Perch & Lever Need Painting

Left Handlebar Control & Lever After Bead Blasting

Left Handlebar Control & Lever After Bead Blasting

I put screws into the threaded holes in the perch to keep paint out of the threads when I paint the perch. I chose a matte black caliper paint for a better match to the new right side perch which has a matte finish. After the paint dried for 24 hours, I baked the perch and lever in the oven for an hour at 200 F to harden the paint.

Screws Threaded Into Holes To Keep Paint Out Of The Threads

Screws Threaded Into Holes To Keep Paint Out Of The Threads

Repainted Left Handlebar Perch & Lever

Repainted Left Handlebar Perch & Lever

Repainted Left Handlebar Perch & Lever

Repainted Left Handlebar Perch & Lever

Revisions

2020-04-05  Add Triple Clamp Refinish section.
2020-05-08  Add Brake Plate Refinish & Rear Brake Stay Painting section.
2020-05-15  Add Front Fork Lower Slider Repaint section.
2020-07-12 Add Transmission Refinish & Cover Repair section.
2020-07-20 Add Handlebar Perch Painting section.

4 thoughts on “51 BMW 1983 R100RS Repair, Refinish, Paint

  1. Hey Brook….you do a beautiful restoration!! As I prepare to embark on my 78′ R100Rs restoration, i’m learning a ton from you….thanks a bunch…Eric

    • Hi Eric,

      Thank you for the kind words. It’s good to hear you are going to keep another airhead on the road. Best of success on that project.

      Best.
      Brook.

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