Rear Brake

[gregtexas]

51 SQ four the rear brake has a large spring attached to the brake pedal casting, causing the brake pedal to be very high in relation to the foot peg.
Something is off with this set up. My brake rod goes down under to the rear brake and I have seen a few photos of the brake rod going up to the rear brake.
here's a photo.

[phil.auldridge]

Hey Greg,
Have no worry, the pedal height will resolve itself once you get your footpegs on. It turns out that the left side footpeg itself functions as the "stop" for the brake pedal (the pedal, of course, to be positioned UNDERNEATH the footpeg), and, you will note the footpeg is on a "cranked" shaft, so you just rotate the footpeg as necessary to the position giving you the desired height of the brake pedal. A bit kludgey of a design, but it functions well enough, and allows quick and precise pedal height adjustment.

As far as the routing of the brake cable and actuator arm, you are very observant. The earlier years such as yours and my own '53 MK II did in fact use the lower routing of the brake cable, while the later models routed the cable over the rear axle, with a corresponding positioning of the actuator arm.

There have been many comments stating that the lower mounting configuration can contribute, in certain instances, "servo-braking".. i.e., as brakes are applied aggressively, supposedly if the chain is too tight, the change in geometry can cause further "auto-engagement" of the arm (and brake) and actually lock up the rear brakes.

It is possible to reposition both the brake arm and the cable to the top position by drilling new mounting holes and replacing the arm with an appropriate one from Draganfly. I considered this enhancement to my bike, but then got discouraged at the scope of the work vs perceived benefits. I've put some 2,000 miles on my bike since ownership without a hint of any auto-servo braking (I do maintain a slightly looser drive chain as a precaution).

Although there have been a few documented instances of rear brake lock up, I am of the opinion that this issue has been more a matter of folklore than a serious model-wide concern, especially considering the number of bikes and miles that have operated successfully without incident. Others may disagree. Of course, I ride my Square Four always respecting its age and design limitations.

What's the old pilot's saying: "A superior pilot is one who employs his superior judgement to avoid situations that might require his superior skills". I suppose that can be applied to bikers as well.