Well, I took the clutch off again to see if I could figure out what the foc was happening and had some success. The bent bit of the selector arm that forms the stopper for the return spring for the claw was colliding with the pins of the selector drum… presumably because the claw pivot has developed a bit of slack, requiring the arm to move a bit further before it's able to drag the drum round out of the neutral detent.
http://gfycat.com/UnlinedSoreElk
The solution seemed straightforward: pop it in the vice and increase the bend of the tang to 90º so that it has some clearance.
![[Image: gearbox3.jpg]](https://s7.postimg.cc/fv2mh0l0r/gearbox3.jpg)
This worked brilliantly… nice positive engagement of first and second. Oddly though, over the course of the next two weeks the problem gradually returned until it stranded me on my way home from work at midnight again… fortunately this time at my local Sainsbury's filling station which is a) covered and b) brilliantly lit. So 15 minutes was all it took to get the cover off and manually prod the drum round to 3rd to limp home.
A bit baffled as to why the problem had come back when it had been so convincingly fixed, I measured the position of the tang and found it had crept back to the original position. Strange steel this thing is made from. So I repeated the bending trick, this time going a bit further so that it got the message… and discovered I'd now got a nice stress fracture across back of the bend. A blob of weld fixed that, and hopefully that will have got rid of the peculiar memory effect.
![[Image: weld.jpg]](https://s8.postimg.cc/gihfeonet/weld.jpg)
So far, so good. All gears select cleanly again.
I suspect that wear, or bending as a result of heavy-footedness, of the claw mechanism rather than any inherent flaw in the gearbox itself is the root cause of the model's second gear problem. Bending the tang, or perhaps chamfering the edges, allows the arm to move far enough to do its job. Excess movement is now limited by the main return spring stop.
http://gfycat.com/UnlinedSoreElk
The solution seemed straightforward: pop it in the vice and increase the bend of the tang to 90º so that it has some clearance.
This worked brilliantly… nice positive engagement of first and second. Oddly though, over the course of the next two weeks the problem gradually returned until it stranded me on my way home from work at midnight again… fortunately this time at my local Sainsbury's filling station which is a) covered and b) brilliantly lit. So 15 minutes was all it took to get the cover off and manually prod the drum round to 3rd to limp home.
A bit baffled as to why the problem had come back when it had been so convincingly fixed, I measured the position of the tang and found it had crept back to the original position. Strange steel this thing is made from. So I repeated the bending trick, this time going a bit further so that it got the message… and discovered I'd now got a nice stress fracture across back of the bend. A blob of weld fixed that, and hopefully that will have got rid of the peculiar memory effect.
So far, so good. All gears select cleanly again.
I suspect that wear, or bending as a result of heavy-footedness, of the claw mechanism rather than any inherent flaw in the gearbox itself is the root cause of the model's second gear problem. Bending the tang, or perhaps chamfering the edges, allows the arm to move far enough to do its job. Excess movement is now limited by the main return spring stop.