Originally Posted by Wolfgang55
If this helps then fine. In 1964 I bought a El Monterdairo. (bad spelling)
I lived in Spain at the time. It was a 4 speed, 350 or 360 cc.
The owner of the shop said it was the biggest motor at the time for Bultaco & used a proven transmission. I think that means the trans was an old design & motor was a recent design.
the montedero is a right kicker - i would think the trans would be different. maybe not.
as for proven transmission, i think the only thing proven about them is that you are proven to find neutral in between every gear :)