All the Bandito and Montadero models were imported into Australia.Model 17 was the first a 350 Bandito followed by the (M18)360 Bandito.This was also the basis for the M51 El Montadero(black/white with lights)These bikes all had close ratio gearboxes.
Next was the M61 (350) and M65(360) also close ratio.These bikes had a redesigned frame which moved the motor and footpegs forward some 70mm,repositioned the swingarm and cured the Bandito light front end which made it steer properly.These bikes had aluminium mudguards like the Montaderos.
The first true El Montadero (M70)had the redesigned frame and a wide ratio gearbox(4 speed). It also had the heaviest magneto flywheel(Electronic dual plug) ever fitted to a motorcycle,consequently it had broad smooth power.
The last Montadero (M81) was in effect the same as the model 70 except for a new exhaust,airfilter,seatcover,front wheel driven speedo,compression release,bash plate.They also decided to lighten the flywheel.It was also wide ratio. (too wide !)
All the models(from memory) had the same cylinder(M18) except the M81 which gained a pair of finger ports like the pursangs of the time.
I have a M70 that I have ridden at Nepean and Coffs dirt track and it is a fun bike to ride,they go well and the later ones as mentioned handle well.The Montadero ratios (wide) are not really suited to dirt track or motocross and gear changes must be done correctly when racing or else! Even when stripped down they are a heavy bike. It is a unique bike(they made about 1K of them).Whenever I ride it I am always laughing inside my helmet!