Gearbox help please

[MJM_58SR]

Hello all
Could I get a bit of a discussion going on my gearbox please.
The casing is stamped 42-3005, inner bit is stamped 67-3345 and selector forks are both stamped 67-3118. The cam plate isn't stamped but looks like it is 67-3332.
I can't see any stamping on the gears and can't find any reference to sizing at the minute.

I have stripped it as it was a real pain to try and go down the gears, the selector plate was chewed so renewed that and put a new spring in.

Looking at some other posts on here there was a discussion about selector forks which suggest part number 67-3204.

Could anyone give me any pointers so I can check what I have and if the box is full of compatible parts or it's a mixture!
I've done some digging and spoken with a couple of previous owners and they said it wasn't a great gearbox and is why they eventually got rid of the bike!
One of the previous owners said they stripped the box and put a new selector plate in but didn't say they changed anything else.

[JulianS]

67 3118 is a forging number on both part 67 3118 and part 67 3204.

part 67 3118 has a web.

67 3204 is a modified forging and does not have the web.

67 3204 came into use with a modified gear cluster introduce in 1950.

The original 3118 will not fit the improved cluster because the web fouls one of the new pinions.

Photo shows the 2 parts original 3118 with web at top. I have no doubt that you will have 3204, the lower one, in your gearbox.

[MJM_58SR]

Hi Julian
Thank you for the reply, a couple more questions please.
I've just checked and they don't have the web so all good there. But on close inspection I can't make out if the web has been taken out on them or not.
Are the early type any wider / different to the later type. When I assemble the selectors into the gears one of them sits in the middle but the other one is quite close to the one of the gears (I've not worked out what gear is what yet)
I'm just trying to close off anything that may be causing an issue before I put it all back together again.
Thanks

[JulianS]

A lot of suspected gearbox problems are actually caused by the clutch -especially the 6 spring clutch which has a certain notoriety.

A few more photos may help.

First one shows why the early part does not fit the modified cluster.

Second shows another view of 3118 (top) and 3204 (bottom).

Hopefully photos will clarify.

[MJM_58SR]

Thanks Julian
What I meant by if the web has been taken out is are they the older version and if someone has ground the web out, would the part fit in all other ways part from the web? I'm not sure anyone would bother some no that anyone but just a thought really.
I think I'm happy now, will get it back together over the weekend and see how it goes. Will only be able to bench test it though as the front is stripped off at the minute.

[JulianS]

You can see the slight change in form in the bottom photo where a corner has been removed on the 3204.

[MJM_58SR]

Thanks Julian
Just re read my post and my phone has a mind of its own!
The main thing I was wondering is if someone had ground the selectors to fit. Apart from the web are they identical?

[JulianS]

The differences appear to be the web and the ground off corner. 

[MJM_58SR]

Thanks Julian
I will have a good look at them and start to put it back together again today.

Thinking about gaskets, what's the general thoughts on using gaskets, I've read a few things about to use or not to use. I've got blue hylomar anyway as always use that or kawabond.

[JulianS]

I suggest use gaskets.

The one between the main shell and the inner cover has an effect on the primary drive alignment and the one between inner and outer covers can an effect on the end clearance of the gearchange spindle and quadrant and gearchange spindle and covers.

[MJM_58SR]

Thanks
Will use gaskets, just need to order a main to middle one