51 BMW 1973 R75/5 Powder Coating

At this stage in the project, the bike is apart. I took the frame, sub-frame, center stand,  battery box halves, headlight ears, license plate bracket and thFe handlebar controls to Brad at BFN Industries,  a local company near me in Arvada, CO.

Parts Going to Powder Coater
Parts Ready for Powder Coating

 

Ready for Powder Coater
Frame Ready for Powder Coat – Tie Wraps Indicate Threaded Holes

A week later, I picked up the parts from Brad at BFN Industries.  The total price was $190 and change for bead blasting and powder coating.  I think the price was very reasonable as I got quotes of close to twice the much from some other power coating companies in the Denver area and I’ve gotten notes that others have paid $500-600 for powder coating this many parts in other areas of the country.

When I closely inspected the right side handlebar control, there was a problem with the coating. It was uneven and lumpy.  I took it back to Brad and he said it looked as if some oil or other surface contaminant was on the part even thought the sand blast and clean before coating. “It’s not right. We’ll take care that.”  I appreciate that level of customer service.

The battery box brackets were rough when I took them in and they show that after being coated, but that’s part of the story for a 40-year-old machine, isn’t it? 🙂

Here’s are some before pictures of  the parts.

.Faring braket rust
Frame Corrosion
Paint and rust
Frame Corrosion
Battery Box Rust
Battery Box Corrosion
Rear wheel for keeping shaft from turning
Gunge on Rear of the Frame
Looking for Stress Factures to Gusset
Rust at Frame Gusset
Swing arm disassembled

Swing arm disassembled

Left Control Disassembled
Left Handlebar Perch
Right Control Disassembled
Right Handlebar Perch
Parts Going to Powder Coater
Parts Going Out for Powder Coating

I wanted to powder coat the swing arm, but not remove the drive shaft. So I came up with a “soup can sock” to prevent beads from striking the joint and the bearings.

Soup Can to Protect Universal Joint Bearings

Soup Can to Protect Universal Joint Bearings

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WARNING
Although I got away with my “soup can” method to avoid removing the drive shaft from the swing arm, it’s a bit risky and relies on the powder coat company to be careful when they blast the swing arm. Also, the temperature used to melt the powder coat is around 400-425 F. The swing arm bearings are sealed and the drip point of the grease used is likely closer to 500 F, but the heat may cause the grease to leak out of the drive shaft bearings. So far I have had no problems. That said, the safest approach is to remove the drive shaft coupling so you can remove the drive shaft from the swing arm. I purchased the tool from Cycle Works to remove the drive shaft coupling: you can read about how I did it here:

An alternative it to take the swing arm to your BMW dealer and have them remove the coupling which is about a 20 minute procedure. They can reassemble it for you as well.
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And here are some after pictures starting with the unwrapping.

Powder Coat Presents
Presents from the Powder Coater
Powder Coat - Headlight Ears
Headlight Ears
Powder Coat - Battery & License Plate Brakets
Battery and License Plate Brackets
Powder Coat - Controls
Handlebar Control Perches
Powder Coat - Center Stand
Center Stand
Powder Coat - Fairing Bracket
Windjammer Faring Brackets
Powder Coat - Frame, Sub-frame
Frame and Sub-frame
Powder Coated Swing Arm

Powder Coated Swing Arm

Powder Coat - Some to Cleanup
Over Spray on Vehicle ID Plate – Need to Clean That Up

All the threaded holes look clear of coating but several need some cleanup at the beginning of the threads due to minor intrusion of the powder coat.

One area I need to clean up is a bit of over spray at the edges of the frame identification plate on the front of the steering head.

I got a note after my initial post that mentioned some over spray to clean up and heard about using Permatex Gasket Remover to soften and lift powder coat over spray.  Here’s the stuff.

Permatex Gasket Remover
Permatex Gasket Remover with Applicator

It is pressurized and comes out very quickly when you push the button.  I found it best to hold it upright with the brush at the top and press gently until the white liquid remover is visible on the brush.  Then apply it where you need to remove powder coat.  I cleaned up the badge on the steering head and then moved on to the frame, sub-frame and controls as a small amount of powder coat at the top or bottom thread was evident. When I only needed a small dab, I used a q-tip to apply the liquid remover just where I wanted it.

I put a little of the gasket remover on the bolt threads and then starting it in the hole.  The gasket remover softened the powder coat in less than a minute and by working the bolt in and out of the thread, it cleared the powder coat very quickly.

Put Permatex on Threads of Swing Arm Pivot
Put Permatex on Threads of Swing Arm Pivot
Clearing Swing Arm Bushing
Clearing Swing Arm Bushing Threads

This worked well for all the threaded holes. About 50% of them needed to be cleared at the start of the thread.

The rear brake bushing is a close fit to the brake pin since it holds grease. In this case, I used my Dremel tool with drum sander to clear out the powder coat. I forgot to indicate this hole should be blocked when I dropped the parts off.

Clearing Rear Brake Bushing
Clearing Rear Brake Bushing

It took me about 2 hours to go over all the holes being sure bushings, bolts and such smoothly fit the threads.

Be careful using the gasket remover so you put it where you want it and it doesn’t inadvertently get onto the frame. Keep water and a sponge handy to wipe it off immediately if you get a dab in the wrong place.

I like the look of the powder coat, and clean up wasn’t a PITA. Based on the price and finish, I think powder coating is a viable option for painting tubes and small parts.  I’ll have to see how well it wears over time.

I also took a couple pictures of the “in Boxes” parts pile with restored/refinished parts. This is what I start from when I begin to reassemble the bike.

R75/5 in Boxes
An R75/5 Disassembled Parts in Boxes and Bags
Powder Coat-Frame, Sub-frame, Fairing Bracket
Fairing Bracket, Frame, Sub-frame and Engine

There is work to be done on the engine, transmission and clutch and more cleaning and polishing of a few items such as the steering damper knob below.  But, I’m getting pretty close to that point we all read in a Haynes or Clymer manual, “Reassembly is the reverse of disassembly.” 🙂

 

9 thoughts on “51 BMW 1973 R75/5 Powder Coating

  1. Pingback: 1973 BMW R75/5 Rebuild: Refinishing Headers, Headlight and Steering Damper | Motorcycles & Other Musings

  2. Hi Brook,

    I am intrigued by the fact that you didn’t remove the driveshaft before powdercoating. Did you notice any ill effects after reassembly and running, or have you since learned anything that would contraindicate doing it again?

    I am almost ready to take the R60/6 pieces to the paint shop, and the prospect of leaving the shaft in situ appeals to me since I lack access to a press or to the special tool needed for removal.

    Thanks again for your excellent photos and observations,

    Joshua

    • Hi Joshua,

      Thanks for the note and question. You saw Tom Cutter’s opinion on the Micapeak Airhead forum, so that’s an “authoritative” answer. So far, I have a couple thousand miles on the drive shaft with no odd noises or problems. I did this as an experiment, and we shall see if my method causes and issues with the drive shaft bearings. Following Tom’s advice is the safest method for powder coating the drive shaft housing.

      Best.
      Brook.

      • Thanks Brook. I ended up ordering the tool from Cycle Works and pulling the driveshaft, just for the sake of caution. I figured that the $70 was cheap insurance. One more question – the powdercoat shop I am using here in Seattle is telling me that I need to remove the nameplate from the steering stem, but I notice that you left yours in place. Did you mask it yourself or did the shop do it for you?

        Best,

        Joshua

          • Thanks – that’s what I opted to do (drilled out the rivets with progressively larger bits until the heads sheared off easily). I also chose to remove the driveshaft using the Cycle Works tool, which was pretty easy.

            All the pieces went to the powder coater this morning – I am following your lead and doing headlight ears, centerstand, control perches, etc. Can’t wait to see the result!

  3. I was a little more shade tree. After cleaning, I used rags and masking tape to protect the drive shaft, hung the swing arm from a tree branch and applied several coats of rattle can primer and paint. I expect this coating to outlast me.

  4. I’m preparing to have my R90s frame for powder coating but cant figure out how to remove the head set lock assembly. Not discussed. Thanks

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