Rear Brake Adjustment

[prue1]

OK, my gray matter is disappearing rapidly that is why I need help! When I adjust my rear brake on my 72 XS2 to the one Inch spec, my rear brake will engage when hitting a bump. This happens until the brakes get warm. In order to correct this problem, I need to adjust the brake pedal to engage with appx. an inch and one half of free play (this is too much for me). My first thought was that my torque arm was not moving freely. After inspection, It is. Would this problem indicate that the brake operating arm is in the wrong position on the brake operating cam? Or maybe The brake pedal is mounted on the spindle incorrectly? Or, could an elliptical brake drum be causing this? Does anyone know the minimum spec for the brake drum lining?

I hope this makes sense, thanks to any and all for any help or suggestions.

P.S. new brake shoes were installed appx. 5000 miles ago.

 

[Its been a long time]

Do you have stock hardware? Or aftermarket/custom footrests/brake lever mount? It's easy to get the geometry wrong so that suspension movement applies the brake.

 

[gggGary]

side view of your whole brake set up?

 

[Jim]

72 XS2 to the one Inch spec, my rear brake will engage when hitting a bump.

Spring missing on pedal shaft?

 

[prue1]

Do you have stock hardware? Or aftermarket/custom footrests/brake lever mount? It's easy to get the geometry wrong so that suspension movement applies the brake.

All stock

 

[prue1]

Do you have stock hardware? Or aftermarket/custom footrests/brake lever mount? It's easy to get the geometry wrong so that suspension movement applies the brake.

All stock

 

[prue1]

Spring missing on pedal shaft?


View attachment 261943

Spring installed and good shape.

 

[Mailman]

I’m gonna park this here for your future reference, it’s @5twins excellent tech article about rear drum brakes. It has a lot of info about proper activating arm placement and proper adjustment.

https://www.xs650.com/threads/650-rear-drum-brake-plates.51046/

 

[prue1]

Thanks, great info, I will read.

 

[prue1]

After applying recommendations here, I have adjusted the rear brake pedal on the spindle inorder to tighten up the return spring. In addition, I moved the brake lever on the rear hub to run more north and south. After making these changes, the rear brake is not engaging on bumps during wam up (geometry/physics in play here?). I'll test more in the coming days, thanks all.

 

[prue1]

After applying recommendations here, I have adjusted the rear brake pedal on the spindle inorder to tighten up the return spring. In addition, I moved the brake lever on the rear hub to run more north and south. After making these changes, the rear brake is not engaging on bumps during wam up (geometry/physics in play here?). I'll test more in the coming days, thanks all.