Mystery Disc Brake Mount

I was given a load of old bike parts by my brother, in there is this brake mount. The top holes are IS 51mm Standard, the bottom holes are 38mm ctc. Any ideas what standard this is or where it may be used? Brother can't remember, I blame his age.

It is a flat plate without threads in any of the holes

Ta Chris

Looks like it's for the earlier disc mount spacing as on some Marzocchi forks.

Yes as above. Pretty sure original z1s had this.

If so, would be in demand I'd expect!

Thanks both

I'm not sure about that, a mount for a Z1 would need to have some offset to it or the caliper wouldn't line up with the disc.

Pretty sure that's an adapter for the swingarm of a ca 1999 Marin Mount Vision?

Not sure about the marin. If that was like the b17 the caliper need to be 90°, as bolts frame downward, and brakes on side if that makes sense

Marin swingarms used a few different styles of brake adapter. That one looks exactly like the one for a 1999/2000 third/forth generation swingarm (I built one up a couple of years ago and had to source one).

Also I think for a Z-1 mount one of those sets of bolt holes would be the smaller M5, they wouldn't all be standard M6.

I’ve got one of those here too

And I know exactly what it came from ...... but that spoils the fun a bit doesn’t it?