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:

• 51 BMW 1973 R75/5 Refinishing Techniques

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

• Robert Fleischer: Cleaning exhaust systems; Drilling/cutting/repairing windshields; Noisy fairings/dash; Pesky hollow rivets; Cleaning plastic visors & windshields; Washing the bike; Maintaining the paintwork & aluminum; Sandblasting, Vapor blasting; Bent levers; Repairing fairings & luggage (hard bags); Black plastic & rubber trim
• Robert Fleischer: Chemicals; Oils (not for engine, driveshaft, gearbox & rear drive); Assembly Lubes, Additives, Greases (including spline greases); Loctite, Sealants, Adhesives; Anti-seize Compounds; Electrical Contact Treatment; Waxes; Wheel paint; Tank Coatings; Windshield and visor maintenance; Removing sticky labels and residues; Cleaners (for your hands & for engine parts, etc.); Freeing up rusty fittings (nuts, bolts, etc)
• Robert Fleischer: Luggage, Tank Bags, Windshields, Mirrors, Instruments, etc.; Locks & Keys (except fuel caps); Noisy fairing vibration at the upper dash

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.

• 34 BMW 1983 R100RS Disassemble, Inspect & Rebuild Brembo Brake Calipers
  • Paint Calipers

Before

Here is what I started with.

After

And here is where I ended up.

Rear Brake Plate Refinish & Rear Brake Stay Painting

The rear brake plate and stay were is rough shape.

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.

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.

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.

• Refinishing Bing Carburetors

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

• 13 BMW 1983 R100RS Rebuild Bing 94/40 Carburetors & Karcoma Petcocks
  • Repainting the White On the Embossed Part of Emblem

Before

This is what I started with.

After

And here is what I ended up with.

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.

• Refinishing Rough Cast Aluminum

Before

Here is what I started with.

After

And, here is what I ended up with.

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.

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

I spot painted primer on the bare metal and then painted it 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.

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

After

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.

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.

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.

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.

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.

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.

Pannier Repair

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

• 46 BMW 1983 R100RS Repair Panniers & Plastic

Before

After

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.

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.

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.

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.

Before

After

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.

• 46 BMW 1983 R100RS Repair Broken Sub-Frame Side Cover Tabs

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

Before

After

Triple Clamp Refinishing

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

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.

Valve Cover Painting

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

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.

When I finish painting them, I wait overnight.

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.

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

Here is how they look mounted on the heads.

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.

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.

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.

Repair Void In Rear Cover Mating Surface

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

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.

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.

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.

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.