Removing cam with gear box in bike

Hello all,

I have been having problems shifting through the gears on my MKIII. I recently did a rebuild of the gearbox with new bearings and oil seals (existing bushings/pawl looked OK). The only thing I didn't take apart was the cam assembly, in large part because I didn't want to upset the finnicky alignment with the quadrant and equally in large part because the bolt was very seized and I wasn't sure how to properly lock the cam to get enough torque.

Everything shifted okay by hand after reassembly but once I got the outer cover on I got false neutrals/ the gearbox refused to shift at all. I tried fixing the ratchet spring: no change, so I tore the gearbox back down and now see that the previous owner must have gone deeper than I because in 4th the cam is misaligned with the quadrant (see pics). Shows me for cutting corners

So here are my questions to you guys:

How do I safely/properly lock the cam in order to get adequate torque on the seized cam bolt? When I had it on the bench I tried heat to loosen the bolt with no luck, I wonder if the o-ring is locking the bolt (I had a heck of a time removing one of my primary access covers for this reason).

Is this a bench-only procedure or can I do this without having to take the gearbox off the bike? (really hoping I can do it on the bike)

Would trying to remove the and reposition the quadrant be a better strategy?

I don't know if I'm one tooth off or more than one, so is there a protocol for determining that without having to rebuild everything and find out the hard way?

Thanks guys,
Anthony

Max position for 4th:


Same position with outer cover removed:


Better view of the cam misalignment:

You shouldn't have to remove the camplate to reset the quadrant.
If you rotate the camplate past the 1st gear notch then the quadrant teeth should drop out of mesh with the camplate and can then be reset. The quadrant looks at least one tooth, (possibly two?) too high in 4th.

Hi , you could easily made a pin spanner to hold cam plate , and i found this on classic bike hub .
To refit the camplate, place the quadrant in position, secured with its bolts and washers. The camplate must be positioned so that one of the end grooves in its circumference is across the centre of the indexing plunger hole in gearbox shell. The gear should be meshed with the last tooth but one on the quadrant. Cheers https://www.classicbikehub.uk/Features/article/Norton -gearbox -overhaul

Thanks guys, I just discovered I can do just as LAB recommended. There I go blaming the previous owner but I probably pushed it down too far at some point and messed it up myself. Hopefully I won't have to go as far as removing the cam any time soon, but if a custom pin spanner is the best route that's good information to have . Fingers crossed that the original o-ring holds out for a while!

Anthony

I noticed in your picture that the centre stand bolt is reversed as the bolt heads normally go on the inside of the cradle.
Not important on the right-hand side but with the LH side bolt shank/thread on the inside it can foul the spring leg each time the stand is used and could eventually break the spring.

Ah, thank you for the catch, I'll correct that!

Have you or previous owner RPPOS (Removed Portuguese Piece of S@#t) layshaft bearing ??
Can be done gb in frame. Roller or upgraded phenolic cage ball bearing is the way forward.

Tornado said:

Have you or previous owner RPPOS (Removed Portuguese Piece of S@#t) layshaft bearing ??
Can be done gb in frame. Roller or upgraded phenolic cage ball bearing is the way forward.

Click to expand...

Pictures show it has the roller bearing.

Shimming aside I really appreciate the superblend bearing for letting me get to the internals much easier. If I had made this mistake with a one piece bearing on the lay shaft I think it would have been another magnitude of mess to fix.

Anvill said:

If I had made this mistake with a one piece bearing on the lay shaft I think it would have been another magnitude of mess to fix.

Click to expand...

To extract the selector forks leaving the camplate free to rotate involves removing mainshaft 1st, 2nd, 3rd, layshaft 1st and 2nd gears but not the layshaft.

L.A.B. said:

You shouldn't have to remove the camplate to reset the quadrant.
If you rotate the camplate past the 1st gear notch then the quadrant teeth should drop out of mesh with the camplate and can then be reset. The quadrant looks at least one tooth, (possibly two?) too high in 4th.

Click to expand...

Exactly the same way I fixed the problem. Thanks to L.A.B.

So how do MK111 owners remove the cam plate to weld up or replace the neutral button on it ?
The retaining nut for it seems seized up too . Large vice grips to the plate to jam full stop , against the shell ? Bolt is soaking in penetrating oil for the moment . Heat gun to it ?

Torontonian said:

So how do MK111 owners remove the cam plate to weld up or replace the neutral button on it ?
The retaining nut for it seems seized up too . Large vice grips to the plate to jam full stop , against the shell ? Bolt is soaking in penetrating oil for the moment . Heat gun to it ?

Click to expand...

Will sound crazy: grab it with a gloved hand or a rag and use and impact wrench to unscrew the bolt. If scared of that, wedge in a piece of wood instead to hold it.

Heat unlikely to help - you can't get the heat where needed.