C15S SCRAMBLER GEAR SELECTION

[DAVE BRADY]

Hi,

Excellent illustration of a great repair technique and hats off to Spaceman for persisting in helping jumbo12 with his gear box problem.
This what this Forum and the BSAOC is all about.
The World could learn a few lessons here.

Dave.

[bobby12]

Hi
Have now fitted the replacement quadrant supplied to me by SPACEMAN. I can now engage all 4 gears with neutral being a little iffy at times, I feel that when the engine is running, clutch fitted and oil, the gear change will be more normal, not having had a BSA before not too sure what to expect.
Just two other points I would like to make regarding why maybe my original quadrant did not work, they may or may not be relevant.
1. The chamfered part of my original plungers where they make contact with the cam plate are flat, on the exchange one there is a slight radius on this face which I think would help the plungers to work better, less friction.
2. The plunger hole centres on my original quadrant is about 3mm wider than the exchanged one, this may have contributed to why the plungers did not make the correct contact with the cam plate slots for gear change.
Food for thought!!
Once again, I would like to thank the club members especially SPACEMAN, for their time and help on this gear box problem, I would never have sorted it without them and would have reluctantly sold the bike as a non-runner whereas now I can carry on with my restoration.
Members please carry-on helping others as you do, we all appreciate your comments and experience.
Regards, M

[Spaceman]

Having had a chance to have a good look at the old quadrant, the problem now seems to be that the bore for one of the plungers is very rough and the friction produced makes it very difficult for the plunger to be pushed out of the way when it comes into contact with the camplate.

The quadrant has clearly been abused in the past because the retainer plate was very battered. I need to look more closely but the rough bore seems to be scored internally circumferentially. It's possible the plunger rusted inside the bore at some point and some hammer blows were applied to the plunger in order to free it producing the scoring.

I am sure it is repairable but am not sure how at the moment?