[ken will]

This bike with the ICE engine, radiator, etc. weighs 480 lbs.
I can probably remove 250 lbs.
It has a drive shaft with a gear reduction of 2.5 and a rear tire with a 80" circumference. That means if I couple the electric motor directly to the drive shaft, at 30 mph the motor will be turning at about 1000 rpm.
Would a Mars ME-0709 Motor be a good choice at 72 volts.
Will I have to add more gear reduction?

[WarpedOne]

Yes, additional 2:1 is recommended.
You need about 4:1 to 5:1 reduction in a motorbike, otherwise you will have poor acceleration and a very hot motor and controller.