OK, I haven't posted for a long time, again.
And once again there's a change of plan. I chose Alien Power C80100 sensored motor (50kv), which should be much better option than GNGbike 2.5kw (on 72V) motor.
Also, I 3D-scanned the generator so I can use it with Fusion 360 CAD.
For batteries I chose Turnigy 6Ah LiPo-s 20s overall.
So, todays progress:
The motor goes actually inside the crank case, which needs a bit milling the side open.
Diameter wise it fits almost perfectly - crankcase is 80mm dead. I'm gonna mill about 1-1.5mm off the inside wall, because I'm worried about eddy currents.
The whole gearbox will be stressed member of rear swingarm and shock absorber will be connected to upper mount point.
The gearbox case will also be 3D-scanned yet. I found really good place for that.