Hiya Folks,
spotted this on Ebay for cheap as it's got a stuck stem and it's local.
Looks like 60's - no built in hanger - and I think the frame number should be recognisable, but it's been repainted.

BB is Campy 1.37" x 24tpi
Headset is Shimano 105
No idea what the tubing is or if the fork is original.




Frame number:



Rear dropouts:


Headtube:





.

Have you checked the Asian Serial # guide? That's what the serial number looks like to me.

Asian Serial Number Guide

Yep I was thinking that frame number looks quite distinctive.
I had a look at the asian guide after I posted since the serial number reminded me of something I'd seen.
Closest in there is

S(3) (Japan): sMyxxxxx [but that would be month code 'Y']
S(4) (Japan): Sy mm xxxx(x) [y = 'Y', month = '87']
SANKI (Japan): Symmxxxx

But the serial number on this frame seems to be "SY87050058" which is at least 1 digit too long.
The only codes that might fit are

SFxxxxxxxx [F = fortnight alpha character = 'Y']
SMxxxxxxxx [M = month character = 'Y' - nope]
SYxxxxxxxx [Y = year alpha character = 'Y']

But I don't see them in that list.

Got no input as to the maker or year, but looks rather entry-level, (rear dropouts and lugs). It is plausibly of Asian manufacture from the 80s.

I'm wondering, the fork looks to have forged tips with lips, and stamped dropouts.

That caught my eye as well. Possibly a replacement?