Can't help agreeing w the comments on the looks of the MX6.
I personally much prefer the looks of the MX4, tho no doubt the MX6 is a better bike. (I've never ridden either)
MX6's did come in 125s as indicated above. I have the engine out of one that was converted for enduro use back in early 80's. In fact I think its the one that featured in ADB mag in the day.
But its not the usual rotary valve engine that they came delivered with. Its a case-reed engine like the RMs of the 70s & like the 370/400 rotax engine. Apparently they're a rare engine (tho Puch used them in some euro models I believe) & I can't find a head for it anywhere. The water-cooled version is more common, but mine is aircooled, circa 82/83.
Anyone know anything about them?