This is one of those things I try to do to every BMW motorcycle I rebuild.
This area is cracked on nearly every frame I tear down. It is the rear foot brake area which also is the muffler / silencer hanger, and where the passenger foot pegs attach. This frame is a 1978 BMW R100s. If you are considering rear sets on your bike that attach to this section, then I HIGHLY RECOMMEND doing this procedure.
cracked tab near rear foot brake pivot hole on BMW airhead framecracked tab near rear foot brake pivot hole
cracked tab near rear foot brake pivot hole on BMW airhead frame
New piece of metal to weld onto the old cracked section to reinforce the area making it MUCH stronger and no longer prone to cracking.
Welded metal onto the rear foot brake section of a BMW R100S
Finished powder coated frame with the welded metal. This area is out of sight to most people unless they take the rear tire off.
The manual available for this bike is old, with terrible photos. So I am snapping shots of everything while I take it apart. How would this happen in the film days??? Expensively I guess…
Pixels are cheap.
More Photos to come…
Bridgestone 175 rear brake hub. Looks like it will polish up OK.
Bridgestone 175 rotary 2 stroke engine getting a batch in on the parts washer. It was filthy.
Bridgestone 175HS rear sprockets. I can’t wait to clean these up. They are a nice feature on the bike.
When Eurotech Motorsports closed down, they had a Siebenrock R75 power kit on sale but it only had one Stainless Steel pushrod tube. While I was placing an order for the remaining pushrod tubes, I figured that I should get some of the brake shoes that Siebenrock sells.
The shoes they sell are Lucas and I am excited to try them out. They appear softer than the hard BMW shoes.
Hard to tell the future but I think we’ll be taking better braking and wearing down brake shoes over poor braking and shoes that never wear down.
Plus, the BMW kit is about twice as expensive as the aftermarket kits out there.
Here is the back of the front brake hub. Remember to lubricate all the pivot pins with grease:
Pivot parts installed:
Bought the gal a new pair of shoes:
Shoes installed. Take note of the different springs. It is important that the thicker spring goes in the proper place:
Don’t forget the snap ring:
I may end up adjusting the arms once the bike is built and the cable is run but for now, i am setting them up in the standard position. The center of the holes should measure 7 inches.
There is a washer that goes between the pivot pin and the final drive. And remember to lube the pivot pin.
The rear brake shoes were a bit harder to install due to the spring tension. But i find it easiest to install one side, hook up the springs and then bend or snap the other side into place. Make sure everything seats properly.