Turns out it is a 3mb barrel. Someone had lost the powervalve end cap and used liquid metal style putty to cover a metal disc that was stuck over the end. lol very strange!
confused me no end til it turned up. The guy sold me an engine, exhuast and carb. The engine had this wrong with it. The exhaust had been cut and re welded so no longer fit a DT125 and the carb had just about every bolt chewwed up and parts snapped off. Total nob. Luckily it was about worth it for spares so didnt bother with the hassle of returning.
Just re-tap it out to a 6mm thread Toy, it's a 5mm thread as standard, if I'm not wrong, as I had the same problem with my end cap 'popping' off, re-tapped mine, no problems since.
Appears to have no other side to the Powervalve?
