Drain plug for radiator?? Shibaura 1400

[PAT1]

I just got the broken drain plug out of the radiator on my Shibaura 14/1400
It is plastic and doesn`t seem to be a 1/4 or 1/8 pipe thread. One is too big and one too small.
Reckon it is something unique (oddball) to Shibaura.....it is a Showa brand radiator ??
Help

 

[sandyc]

If you can't get the replacement I'll bet that an auto parts store might have an expandable rubber plug that would work for you....just a thought

 

[Cam-Saskatoon Canada]

It might be metric?

 

[PAT1]

turns out it is a 12mm x1.75 bolt pattern. a flat washer and some rubber washers should do the trick.