Category Archives: BMW cafe Motorcycle

BMW Cafe Motorcycle R75 build

POR 15 Gas Tank cleaner and coating

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I’ve used this product before with reasonable success on about 3 or 4 motorcycles now. In one instance, it started to peel from the roof of the gas tank and large chunks would float in my gas. Once i removed them, everything was fine.
Something must have gone wrong with the prep or paint process. I have a feeling it was from the tank drying upside down and the POR15 dried in a puddle that eventually broke loose.

I have a bunch of tanks sitting around and an extra kit of POR 15. Unfortunately, this process takes nearly an entire day.

Follow the directions and you should be good to go.
Try to do it on a sunny day.
OUTSIDE.
It really helps to have a heat gun to speed up the process of drying out the tanks.
Prepare to get wet or splashed.
TAKE CARE TO PROTECT THE PAINT OF YOUR TANK. If any of the 3 step process gets on the tank, it may leave a streak and damage the paint.
Wear Gloves. (see below)

 

The vicitms... ready for a day in the sun.

The first two processes require lots of sloshing liquids inside the tank. Then drying. A heat gun helps speed up the dry time. I hair dryer may work too but not as effectively.

 

 

This photo was taken after the first step, 'Marine Clean' was used. The Marine Clean removed a ton of the rust inside. When i drained it, the water came out Rust-Red.

It looks like a previous owner used the tank cream or something similar. These chunks, and many more came out after the second process 'Metal Ready'. I ended up using a long screwdriver and tried to scrape off as much of this crap as i could. It was a previous tank coating gone wrong. There is still remains of it in the tank. I hope it doesn't cause problems later on. The POR 15 is such a good sealant, i think it won't be a problem.

 

 

Tanks sealed. This process is a messy one. It would help to have an old set of petcocks to use while you slosh the sealant around. then remove them to drain the sealant and dry.

 

 

Out on the porch to dry. They were originally in the garage but they stunk up the whole house.

I went Michael Jackson style and only wore one glove. I got the sealant on my other hand and it sure doesn't look like it is coming off anytime soon. I used paint thinner and lots of scrubbing and... well... the wife isn't happy a day later... opps!

Reassembly of transmission and final drive

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I’m definitely not going to take on these daunting tasks myself.  Just look at all those parts!

Someday when i have lots of extra time and extra transmissions to experiment on, i’ll try to figure this stuff out myself.

But for now, they are going to the hands of  an expert.  Luckily everything fit in the saddlebags of my R100s.

Somehow, those parts are going to fit into that shiny housing.

Final drive guts

Trany guts. Looks like a clock exploded.

BMW parts inside of BMW bags.

parts polishing

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I set a box of small parts aside to be polished when i tore the bike apart. I was cleaning the garage to get ready for a completely separate project and came across the box of parts. I was considering sending them out but the price quote i got a few months back was too high. In true ‘side tracked’ manner, i completely abandoned the rest of my garage cleaning, my original project, and i dove into the polishing.
I did a test first on one of the front brake arms to see if it was worth it.

before and after. The camera makes the scratches look worse then they are. The piece came out chrome-like.

The key to polishing is actually the sanding. The more you sand out the blemishes, the nicer the polish will look. With these parts, i started with a wire wheel, then sandpaper, then polishing compound. I could have spent 8 hours just sanding these parts. At a certain point, i decided to cut my losses. Some blemishes where too deep or not completely necessary to remove.

After a wire wheel and 250 grit sandpaper:

After 320, then 500 grit paper:

After the ‘stage 1’ polishing compound:

Done for now. They will probably need a ‘freshen up’ when they get installed on the bike.
This is after stage two of the polishing compound:

bling bling!

Engine Paint

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After TONS of cleaning, I finally decided on which paint to use. I went with a 1200 degree ceramic based engine paint i had sitting in my garage. I had nearly a full can left from an old project. It seemed to go on the smoothest when i rubbed it on.
Yes, i said rubbed it on… meaning i didn’t spray or brush the paint on, i actually rubbed it into the metal with a rag. After i finished, if needed, i would go over an area with a very light spray.

I desperately wanted the POR 15 engine enamel to work but it did not brush on very smoothly. It went on VERY thick and adds an entirely new surface to whatever you are painting (i tested on a BMW valve cover for my 2002). It looked almost like a powder coat type surface.
It sprayed OK but i didn’t want to spray my parts and worry about masking everything off. The rub technique worked well at times, and not at others.
If you buy it, i do recommend thinning and spraying it. It is actually a nice product. I sprayed one side of a 318i manifold and it looks pretty good. i think the thinner and the spray helped it not go on so cake-like.

Anyhow, back to my ceramic based high temp paint… I started with the final drive and front brake hub. When i finished those, i went to look for more paint only to find out it was discontinued about 2 years ago.
Douph! Just my luck…
I began to think of how much paint i wasted on testing, and spraying other stuff…

Final drive painted. Half the front brake hub is painted.

Done and dry.

With fingers crossed, i made it through the project with enough paint to spare for touch ups (if needed). Phew… it was a nail biter though.

Painted transmission case and engine block.

So clean you could eat off it!

Ready for blasting and coating

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All this stuff is boxed up and ready to get blasted.
Instead of a powder coat, i found a color that is very close to the silver we want… except it is a liquid coat. It is the same material used on racing brake calipers among other items. It gets sprayed on similar to a powder, and baked like a powder, but it is a thinner coat (which is good for parts fitting) and very resistant and durable to chemicals, heat, etc…
I’ll have more information on it tomorrow after i drop my parts off.
My shop turned me onto it last time as we were trying different options to match the color we want to a Porsche silver. This liquid coat was the closest.

Fitting BMW controls onto 7/8 bars

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It seems that every cool aftermarket handlebar out there is for 7/8″ bikes. BMW has a slightly smaller handlebar measured at 22mm diameter.
PURISTS BEWARE (I’ve been criticized for the following procedure before).
All it takes to solve the issue is a Dremel and some grinding bits.
Also, please note that i have already ground down the handlebar mount clamps to fit nicely over the 7/8 bars.

Tools for the job.

Mission accomplished.

Tail Light bracket

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A few final parts needed to be fitted before I can send everything off for blasting and power coat.
Those include a tail light hanger/bracket and small hangers for the rear turn signals.
I found these great old British turn signals. I have no idea what they are for, but for $35, i had to pick it up. The box is dated 1968 and i thought it would make a great tail light. If anybody has any information on it, please contact me? I’d love to know what it was intended for.

WIPAC British turn signal.



Our new tail light

We also bought another rear tail light that comes with a great hinged license plate bracket just in case the British light didn’t fit or work.
Seeing that the British light would work, i decided to incorporate it with the new license plate bracket (it is the black bracket seen in the next few photos).

I made a prototype bracket to hang the tail light from out of a sheet of aluminum i had laying around. Then sent it to a family friend who is a machinist for Coke. He took my template and made a bracket out of thick stainless steel. He made it a bit larger so i had to trim it down.

Bracket development. The stainless steel is a thick gauge and shouldn't 'unbend'.




Prototype tail light bracket.

I found these nice and small bullet shaped turn signals. I plan to have them blasted and coated to match the rest of the parts. Unfortunately, the small holes on the subframe that I intended to hang them from conflict with the lower edge of the seat cowl. I thought about trimming the seat/fiberglass but it would disturb the lines that the seat makes as it covers subframe.
So i made some small brackets to drop the turn signal down away from the seat.

Bullet rear turn signal



I didn't like how long the stems were so I trimmed them down.

Booty shot.

tail light and rear turn signal

All done. I love a few hours on a Sunday afternoon grinding and drilling metal.