They did exist but much rarer though! – It is now common they are now 5 speed, as is the GT125 bikes.
It is the GT650 and GV650 still to this day share the same engine but the GT650 has 6 gears. (Sometimes the GV does!) – Also depends on the markets Korea sells the bikes to.
Don’t worry though, the 5 speed gearbox on the 125 is more than adequate for it as the 6th would be like some kind of overdrive gear.
Thank you for that info Marcel, it has shed light on that. I have no intention of altering mine but info is useful. I will keep my eyes peeled for an old 6 speed 125 as it has peeked my interest.
The fact that the 650 shares the same bottom end is interesting also, shows the strength of the 125 set up.