Gearbox selection problem

[bikerbob]

I decided to strip the gearbox on the 1956 A7 because there was play on the main shaft at primary end. Renewed all bearings and bushes and rebuilt the box but was having problems selecting the gears with box on the bench so stripped it down again but could not find anything wrong ,rebuilt the box gear selection was at first okay but then same problem . Stripped box down again but could not find anything wrong at first, but after refitting the gear cluster before fitting the covers I moved the camplate with a screwdriver and all gears were selecting at first but then the camplate plunger suddenly stuck down and would not spring back up. That was the problem, most times it worked but then it would stick, I dismantled it cleaned it then refitted it and it worked perfectly until you tightened the lock nut up then it would stick. I had it in and out a few times but every time you tightened the lock nut it would stick for some reason, fortunately I had a spare gearbox and swapped  the plunger units over and now all okay  box ready to go back. Funny that it was not sticking before I stripped the box down  there was quite a bit of sediment in the bottom  which I thought was the cause of the sticking. The moral is of course check everything before fitting the covers.

[muskrat]

G'day Bob.
You would now qualify as a g/box expert. I'd say by tightening the nut it's squeezing the tube a tad and causing the sticktion. Problems surface in the most unlikely places.
Thanks for posting.
Cheers

[wilko]

Whenever checking gearbox selection on the bench always spin the mainshaft.

[bikerbob]

 I think your correct Muskrat because if I turn the plunger around and insert into the holder it goes about half way down then gets tight not to tight that I cannot take a bit off with a bit of wet&dry and free it up and yes I know that when the box is on the bench it helps if you turn the mainshaft also if you hold the sprocket with one hand and can turn the mainshaft then you are in neutral.