Has anyone seen this on a villiers iron barrel? 

No. Probably been on a kart at some point

Looks like the port has been enlarged and a bridge added, I haven't seen that on a standard barrel Villiers motor before.

I'd go with the karting suggestion. They used to cut away so much metal. The big name was Upton. 

I don't know what your intentions are but Id be very wary about spending money on a barrel like this or a piston to suit if you're planning to put it on a trials bike. A good chance its been tuned for something other than trials

Edited December 2, 20196 yr by faussy

It came on a engine I bought. I would not use it, building a 37a spec lump for a 67 anglian, my thoughts were cart as well