Questions, why not planetary gears? Also do you plan on sensoring the motor or it’s hall sensored and you’ll drive it in velocity instead of absolute position? What reduction ration you aim for? Also if you must use belt/pulley why not put the motor inline with the arm axis to act as a counter weight to gain more arm torque, behind the arm pivot point?
Yes sensored motor. I did not think of the tipping point. Merde… No keykaps 
The belt runs through the extrusion. I want the motor close to main frame
The gear ratio, i believe will be 1:5 and 18-21 teeth on the GT2 pulley
If one was to mount it to a road bike, I guess you would attach a chain gear to drive a geared front wheel and some sort of frame mount. You should be able to calculate the gear ratio for a typical 11 speed cassette. @24v the max speed will be around (190 kv x 24v) 4560rpm/5 (gear ratio primary gear) = 912 rpm(no load).
You would need a custom front fork with some clever suspension
(post deleted by author)