Those motors turn up a lot in pre 70 projects, and flat tracker frames where set up for the X6 motor which was a fast 2eee, back in the day with the Pro-Novice Dt guys. Theyd give the standard bzas and trumphs a run, 145mph from the factory so they say, if its got that version motor in it, has be worth it just for that.
The X6 or previous T20 where the first six speed close ratio boxes in the world. They got put in all matter of frames, was really the precuser to the fast YAm RD 2 smokers.
So be interesting to see what that thing has for a motor and condition in there. IN the states i think they refered to them as a scrambler but they were more like the bikes of the day that did a bit of everything.
Yours might be a 67 going by the tanks curve, make an awesome PRe 68 Dt racer, i think i can hook up a frame for that donk too in a trackmaster.
shes a bueaty regardless, even ol' MX250 mate leno luv that kind of thing
http://www.jaylenosgarage.com/video/video_player.shtml?vid=239038- Beside's i though you where getting out of bikes - that will teach ya