The idea of a four speed Motom came from studying the vijf speed project I'm working on.
A stock Motom has an extra shifting possibility for starting the engine with the petals.
You can use that shift point for the fourth gear.
![](images/ewdfw.jpg)
Possible to use the gearshift mechanism.
Enough room for the last gear, it stays inside the normal cranck case.
Should be doable.
Drill a hole for the ball, and seal it off with a spring lock.
Enlarge the shaft with 8mm, ore make a new one.