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Re: 1971 R75/5 Partial Restoration

Posted: Thu Dec 24, 2020 11:55 am
by schrader7032
My bad...the stamp on mine is on the left side on the flat part just above the upper left mounting bolt. I think we ran into this with another member...srankin...he couldn't find a mark either.

Re: 1971 R75/5 Partial Restoration

Posted: Thu Dec 24, 2020 12:14 pm
by srankin
Some of the ride off stands don't have numbers stamped on them. I have one on hand now.

As I have said, since I installed my first ride off stand on my RT, I have not had the bike fall over, or dig into the ground. I rarely use the stock side stand.

I did learn however on my 78RS, the center stand mounting points on the frame are weaker than the the 84RT. I have had one issue with the ride off stand on the 78 where they were bent and the stand didn't work properly. For now, I don't ride off with my weight on the bike, just rock off the stand. St.

Re: 1971 R75/5 Partial Restoration

Posted: Mon Dec 28, 2020 8:09 am
by skychs
Yesterday was football but I did manage to modify the original BMW ignition key over to the new ignition. To remove the key peg I drilled all around the peg until it broke loose. On a grinding wheel I reshaped the head of the new key to fit into the original head. I heated the key to set the mold in the head. Then I used super glue to lock in the key. After Im confident it will work I will use some kind of epoxy to make it permanent.

Re: 1971 R75/5 Partial Restoration

Posted: Mon Dec 28, 2020 8:27 am
by skychs
Yesterday I also discovered a problem. The seat latch receiver or the hole the seat peg sits in when closed is tack welded in two different areas on the top of the frame. One of the tack welds is loose. The peg on the seat is broken off and the seat latch to hold the peg was all beat up when I took the bike apart. I was able to rebuild the seat latch itself. It was missing a "c" clip and it was full of dirt and grease. Now I have to figure out how to secure the latch to the frame. In the photo you can see the right tack weld is loose. There is a line on the latch that looks like a crack but it does not move.
Suggestions ????????

Re: 1971 R75/5 Partial Restoration

Posted: Mon Dec 28, 2020 8:57 am
by srankin
If you go to Brook Ream's website, he has a fix for the missing c-clip, just wind a bit of fine wire on the end in place of the clip.

As for your cracking problem, wow! I can see the PO, hammered on the system instead of fixing it and now, you have the problem.

Correcting the seat latch mechanism and the seat peg so they work the way should will prevent further damage but, what to do with this break? Are you sure it is a real crack or perhaps just a flaw in the powder coat?

Can you tell if there is any movement of the plate? If not, you may get by with doing nothing now you have things properly adjusted. Time will tell if things need to be further worked on as in if the crack gets wider or longer.

Other than stripping the powder coat and welding, I see no other fix at this time. I myself would let it go and see if it gets bigger or worse in time. I know it is a disappointment to find this now after paying to powder coat. At least, it is where it can't be seen. If it gets worse or it really is a crack, as I said, you now have the seat fixed so the strain is off it that caused the break in the first place. St.

Re: 1971 R75/5 Partial Restoration

Posted: Mon Dec 28, 2020 9:27 am
by skychs
I actually had a "C" clip for it. It slipped right on and works fine.

With the broken seat pin and now the frame ..... its obvious that area of the bike was used and abused. Im sure most of it was caused because of the mechanical latch itself no working properly. These old BMW's are tough but they still need to be treated with care. Understanding "how" everything works is a plus.

With light touch the crack does not move. Im afraid to pull hard on it but something needs to be done down the road. The owner of the bike said he can weld. Maybe he has a suggestion.

Re: 1971 R75/5 Partial Restoration

Posted: Mon Dec 28, 2020 12:33 pm
by srankin
I know you have a freshly powder coated frame and don't want to go to the trouble of tearing things apart to fix this.

I would strip off the powder coating in the area of the crack. This will give you a better idea of the damage and if in fact it needs to be welded. Welding will require more of the powder coat to be removed than just the bit around the crack. I hate to see you do a lot of work to find a minor problem.

If the crack is a real problem, then it can. be addressed as needed. If you strip the bit around it and it is not a problem, a bit of black paint can be blended in with care.

LOL, if the Previous owner did the damage to the bike, he would be the last person I would let weld it. A bit of care in the first place and the problem would not exist. In other words, I find people who cannot maintain things in a proper manner are not the kind of people I want to do work for me. Good luck. St.

Re: 1971 R75/5 Partial Restoration

Posted: Tue Dec 29, 2020 8:30 pm
by skychs
Thanks for the input. Today I talked to a friend of mine who works on Vintage BMW's and is a welder. In fact I bought my 66 R60/2 from him in 2016. He said he would be happy to help. I will let you know what he says.

Anyway, yesterday I finally got the handlebar controls from the powdercoater. Much better. So today I installed the controls and began attaching the throttle, brake and clutch cables. With the wires from the controls I was able to continue with the wiring in the headlight. One wire at a time. Ill post the wiring diagram Im working with.

I also printed and used the front wheel brake "cheat sheet". It makes setting up and adjusting the brakes much easier.

Re: 1971 R75/5 Partial Restoration

Posted: Tue Dec 29, 2020 8:38 pm
by skychs
Some electrical progress. Even though Im installing the new ignition key set the plan is to complete all the original wiring THEN wire in the new key set. Id like to test all the circuits before I re-wire it.

The front brake is set and adjusted.

Re: 1971 R75/5 Partial Restoration

Posted: Wed Dec 30, 2020 1:32 pm
by srankin
Keep going in the right direction, I reading about your progress.

The progress on my bike has stalled due to other things interfering. St.