Tag Archives: r75/5

Blasted

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I love bare steel.
I got a call from the powder coat shop yesterday. My parts are blasted. I went down there today to go over what needs to be masked and not coated. I spent about an hour roughly taping things off. I can’t imaging how long it will take somebody to mask it all properly.

hubs, fork sliders, center stand, final drive.

Frame (and somebody's car rims).

Little bits. Final Drive.

Even smaller bits.

Some Stop Tech brakes.

More Stop Tech calipers. After they get coated, there is a crew of women who screen print the logos on them.

Men at work... plugging and masking.

Men at work... spraying.

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.

Final Drive gutted and cleaned

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On this bike, i am being much more thorough then my own. Because this is going to end up in another person’s garage, i am going through everything i can to ensure minimal issues aside from wear and tear in the hands of a new owner.
I’ve had the seals go bad on my final drive(s) before so i figured i might as well have these gutted, clean them, get new seals, etc… In between all this, I plan on coating the exterior with the same substance i plan to use for the engine and front brake hub.
Out of the two final drives from the two donor bikes, one had a really good set of splines. It has really helped to have an extra donor bike.

Please note, if you remove the innards of your final drive, there is a bearing that can NOT be replaced. It is in the cast of the aluminum. If that bearing goes bad, the whole final drive is ruined. I guess all early 70’s final drives were built this way and BMW finally made final drives in which the bearing could be replaced in the lat 70’s and 80’s.
So if you take apart your final drive, keep that bearing lubricated so it does not dry out and get ruined.

BMW R75/5 Final Drive with gearing removed

Gutted and cleaned 32/10 rear final drive from a R75/5 BMW

Dirty Exterior Final Drive

Cleaned final drive. Ready for coating...

Rear Set mount preparation

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Before i get the frame blasted and powder coated, i did a test fit with the rear sets. On my last bike, i mounted the rear sets to the plate that the mufflers hang from behind the swingarm bearings. I had to create angled shims to get the rear sets to mount perpendicular to the frame. If they didn’t have a shim, the rear set foot pegs would point slightly forward.
The same holds true with the Disco Volante rear sets i am using on this bike. Lesson learned from the last bike… this time BEFORE powder coat, i enlisted a welding buddy to help me create a solid mounting area for the rear sets.
In addition to the rear set mounts, i am also going to fill the holes for the passenger foot pegs and the saddle bag mounts.

BMW R75 swingarm pivot and muffler hanger plate





Rear set mounting hole but notice the gaps.





Small gap on the right side foot peg





In addition to making a better mount for the rear sets, i need to fix the common crack that occurs on the mounting tab. It is often caused by road elements, or the battery drain tube, or rear passenger stress, etc...



AFTER PHOTOS:

New Rear set mount and passenger footpeg and saddle bag holes filled.





Nice and perfect mate between the foot peg and frame.





perpendicular foot peg mount.





another perpendicular shot





Shot of the inner side. My buddy welded the crack and then went a bit overboard with the thickness of the plate he welded to reinforce that area. But I figured it couldn't hurt to have too much metal back there. Especially if that plate will need to handle the weight of somebody's legs/body.





I did a bit of sanding and polishing to smooth the area in preparation for powder coat. It is going to look nice and clean back there instead a stock frame with the passenger footpeg holes and such.