Wednesday, June 27, 2012

Rear brake and gear change foot controls

The rear brake and gear change levers are operated in a similar way. The levers both pivot on a shaft that extends from the rider's footrest. The shaft then passes through a substantial alloy casting (previously restored) and is bolted up with a M10 button-headed allen bolt. 
Brake lever, footrest incorporating pivot
lug, and alloy casting. The bottle is thread
lock solution, to be applied to the footrest
retaining bolt. 

The levers have a lug extending from beneath the pivot point and to which is attached a linkage rod to the rear master cylinder, in the case of the brake lever, or a short secondary lever on the splined gear change shaft, in the case of the gear lever. Both levers benefit from the protection and lubricated action of a special bush (phosphor bronze?). How nice, once again, to see evidence of a design team who cared about the long-term viability of the machines they were creating


The brake lever is attached to its operating rod by a simple clevis pin. I fitted a stainless washer and R-clip to the clevis pin the clevis pin, along with plenty of grease.

The gear lever is attached it operating rod via a rose joint, with another rose jointed coupling for this little rod on the gear change shaft. They get a lot of action in a harsh environment - down low on the bike in the wet. I carefully forced as much grease as I could into the joint using a small screwdriver, holding the joint to make a gap between its internal ball and external housing, and rotating it frequently to spread the grease around. Result: beautiful smooth action.


The footrests were loose when I got the bike and the bearings dry. It isn't easy to do them up off the bike - impossible with the alloy plates installed. It's no small matter to lubricate them either so again plenty of grease here. I used threadlock compound to help keep them in place. In any case, I found it was a bit of a challenge to torque up the M10 retaining bolt off the bike. After trying a few different ways to hold the alloy casting, I found I could clamp it at an angle in my notWorkmate.


After all that, bolting in place with two M8s, one into a captive nut  and the lower one into a separate locking nut, means I have a place to put my feet and, though I say so myself, a great gearchange action.



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