- Product Mentions
- Other References
- Refinishing Rough Cast Aluminum
- Refinishing Bing Carburetors
- Refinishing Chrome Headers
- Refinishing Faded Black Plastic
I’ve had several questions and Email about how I refinish the rough aluminum casting on the engine, transmission and rear drive and also some questions on how I got the carburetors to look shiny and new again.
NOTE: Refinishing is not rebuilding. Refinishing is restoring the surface of parts to “like new” condition. You are removing crud, stains, grime, dirt, grease, bugs, corrosion, tar, mud and old gasket sealer that have frequently been baked on for 10, 20, 30 or more years. It takes PATIENCE. It is applied Zen 🙂
I make reference to specific products not to say these are the ONLY products that can work, but to be clear about what products I have used. YMMV. In particular, I have used AutoSol metal cleaning products and keep several of them handy. Here are links to the manufactures sites for you reference.
- Metal Polish, Liquid
- Aluminum Cleaner, Spray Liquid
- Aluminum Polish, Paste
- Aluminum Protective Oil, Spray
- Bluing Remover For Headers
Hardware Store (Ace, Home Depot, Lowes, etc.)
- Scotch Brite Pads
- 600, 1500, 2000 Grit wet/dry paper
- Steel Wool, “00”, “000”, “0000”
- Nylon brushes
Auto Parts Store (Napa, AutoZone, O’Reilly’s, etc.)
- Brake Cleaner
- ChemTool B-12 Carburetor Cleaner
- Engine Degreaser
- Parts Cleaner Solution – NAPA: Aqueous Solution
Here are some references I’ve found that have advice, information about cleaning methods, product lists and ideas about refinishing techniques.
- Bob Fleischer, Maintaining the Paintwork and Aluminum
- Mark Holbrook, Cleaning Aluminum Engine Components
- WebBikeWorld, Motorcycle Metal Polishing Reviews and Information
Refinishing Rough Cast Aluminum
There is a lot of cast aluminum in the R75/5: engine, air box halves, intake top cover, front cam cover, transmission, rear drive, lower fork tubes, front brake plate, and wheel hubs. Here is what I started with.
I start with engine cleaner to remove as much of the baked on grease and grime as I can. I use several kinds of nylon brushes, Scotch Brite pads and tooth brushes to get the junk off. I used engine cleaner on the entire bike before I brought it into the shop. I also used it to clean out the inside of the bell housing around the clutch and the exterior of the engine. I use a spay bottle of water to wash off the cleaner onto a thick layer of newspaper on the shop mat to soak up as much of it as I can.
Brake Cleaner and Parts Washer
After I got the gunk off with engine cleaner, I put the smaller parts that fit into my parts washer and use the nylon brush and tooth brushes to get any remaining crud off. I use brake cleaner on stubborn stains and baked on tar. I also used it on exterior of the engine.
Scotch Brite and AutoSol Aluminum Cleaner
For the rougher castings found on the engine and transmission, I use Scotch Brite with the Autosol Aluminum cleaner. This usually removes stains from leaking battery acid, gear lube and oil.
This comes in a variety of roughness. I use “00” rougher up to “0000” very fine. I use this with the Aluminum Cleaner to really renew the the pores in the cast aluminum. It quickly brings back a sparkle.
Wet/Dry Sand Paper 600 – 2000 Grit For Scratch Removal
Some parts that were polished had scratches in them. For example, the shock covers. I used wet/dry sand paper starting with 600, then 1500 and finally 2000 grit to remove the scratches. Then I polished them with Griot’s polish starting with Polish #1 and ending with Polish #3. Then I finished up with Aluminum Polish.
Metal Polish, Aluminum Paste Polish, Aluminum Protective Oil
The last step is to polish the aluminum. For rougher parts, i use the AutoSol Metal Polish. For polished aluminum or fine grained castings, I use Autosol Aluminum Paste polish. I apply this with blue shop towels and remove the blackened residue with a clean section of the towel. I finish up using a microfiber towel. Finally, I spray the part with AutoSol Aluminum Protective Spray and let it sit for about 30 seconds and then lightly buff it with a clean microfiber towel.
Here’s the results.
Refinishing Bing Carburetors
To be clear, this covers cleaning and polishing the EXTERIOR of the carburetor body. I do NOT use abrasives, steel wool, etc. on the internal parts of the carburetor, only the exterior of the carburetor body.
Soak in Parts Cleaner Solution Overnight
I started with this (on the left) and ended up with this (on the right) after soaking the entire carburetor in parts cleaner overnight.
Then, I use a tooth brush and my parts washer to remove any remaining dirt and crud off the outside of the carburetor.
Disassembly and Soak in Carburetor Cleaner
I use Chemtool B-12 carburetor cleaner. WARNING: This is very nasty stuff. It eats nitrile gloves. Use rubber kitchen gloves when handling it and keep it off your skin. Wear safety glasses when working with it.
I disassemble the carburetor and soak all the parts overnight in bins.
This is what the body looks like after I use a tooth brush with Chemtool B-12 to clean any remaining varnish and crud out of the creases and crevices of the carburetor body.
Polishing Exterior of Carburetor Body
Here are the basic tools I use AFTER I have soaked the carburetors in Chemtool B-12 carburetor cleaner overnight followed up with a tooth brush scrub with B-12.
Most of the work is done with “0000” steel wool and AutoSol Aluminum Cleaner. I spray the AutoSol cleaner and then use the steel wool to return a shine to the aluminum. In the hard to reach places. I use the the brass wire brush and brass Dremel tool to get into some of the curved and hard to reach creases in the body. I use a lot of blue shop towels to clean the blackened residue off as I go. Next, I use the AutoSol Metal Polish and a blue shop towel to bring the luster back to the aluminum. In hard to reach places, I put a brittle brush on the Dremel tool to polish. Again, I use a separate blue shop towel to buff and remove the black residue. I sometimes use the AutoSol Aluminum Paste polish. It works well on already polished surfaces but I find the liquid Metal Polish works better on the rougher cast aluminum found in the carburetor body. I polish up all the exterior metal hardware (linkages, levers, nuts, etc.) using the Metal Polish and-you guesed it-more blue shop towels. Here is the final result after several hours of applied elbow grease.
Refinishing Chrome Headers
I have used AutoSol Bluing Remover and Semichrome paste with good results. You can read about the work I did to refinish the header pipes here:
And here is the Before and After pictures.
Refinishing Faded Black Plastic
I got a comment from a reader that I should try “Forever Black” on faded black plastic to restore the sheen. I tried that on the handlebar switches and I think this is going to be my new “go to” for plastic restoration.