Help! Anyone know what gearbox this is? TZ125?

[Viper666]

I bought this gearbox from the US a while ago. It was suppose to be a YZ125E box but as you can see it isn't. I have been to the Yamaha site and the only thing that comes close is a TZ125. Suppose that's where we got our wires crossed. YZ, TZ?
The shift drum is unusual as it has a large boss at the end and a fine ring like the old style drum but the cam end has the small welded ratchet like the post 80's. The shift fork shaft has a step in it that must go through the case. The shafts and gears look like a 125 or a modern 80/85.

Anyway, if anyone knows what it is I will be greatfull as I am about to have a huge shed clean out.
Nos parts & plastics. Mostly YZ 77-81 but some IT and Susuki stuff that's lying around.
When I get it all sorted out I'll post a list of sorts.

Gears are 1st 13:30, 2nd 15:28, 3rd 17:26, 4th 17:22, 5th 20:23 & 6th 21:22

[Lozza]

I might be interested in it can you post a pic or count the teeth on both first gears, the ratio will tell me if it's a TZ. Approaching 2:1 will be a TZ.

[Nathan S]

Gears are 1st 13:30, 2nd 15:28, 3rd 17:26, 4th 17:22, 5th 20:23 & 6th 21:22

 
You can see that its a very close ratio box -closer than any of the old YZs, for sure.

[Lozza]

Definantly TZ the long clutch shaft indicates a dry clutch to. I'll send you a PM when I establish what model it came from.Is it possible to take some measurements of the shafts where the bearings sit and the overall lengths of the gear cluster?

[Viper666]

Thanks Lozza.

I'll measure it and post when I can

Viper666