Bicycle Based Lightweight Motorcycle

So late in 2015 I wrapped up version 1.0 of my 2wd electric bicycle.
This year I have decided to revamp that bike to make it a little more tidy.
I have about wrapped up that build.

Anyway I will be riding that bike around for a bit but I have decided that I want to build a new bike.
This time around I will pass on the pedals and make it strictly motor/battery powered.

This bike will be primarily for commuting around town and will see very little highway use.
I have been on this forum for a bit now and I generally do a bit of research before I start tossing questions out there.
However, this time around I can't quite sort out exactly what I need to accomplish what I want.

So, realistically I would like to to be able to travel about 20 miles on a charge.
The tiny town I live in is only 2 or 3 miles across depending on which direction you go.
I would like to be able to cruise around town for a day without too much worry about running short on the juice.
My current bike does this pretty easily and it works.
The only difference is that my current bike tops out about about 24mph.
Generally it does this with about 800 watts (I think? its been a few months since I have ridden it and monitored the power) and me pedaling at a non-exhaustive pace.
Ideally I would like to be able to do 45 or 50 mph.
Realistically it would spend most of its time in the 25 to 35 mph range.
While I do live in a hilly area, I typically do not hit to many serious hills while cruising around town.
There could be a couple of decent hills on the way to a couple of friends' houses but that's about it.

What I have in mind so far will be, for the sake of the conversation, a primarily bicycle based build.
I may end up building a frame and will probably use a dual crown down hill fork and an equally squishy rear suspension.
This will all roll on some 19 inch motorcycle wheels and tires laced up to some beefy down hill mountain bike hubs.
Of course there will be no pedals in this situation.
Hence the thread in the e-motorcycle section.

For motivation I have been looking at a mid-mounted Luna cycle's 3000 watt cyclone motor and controller.
https://lunacycle.com/cyclone-mid-drive-ebike-motor-with-freewheel-sprocket/

https://lunacycle.com/40-amp-36-72v-ebike-bluetooth-programmable-controller/

I will likely fab up a belt drive system so I can toy with the gearing.

This would all be powered by a 72 volt battery.
I have not sorted out whether I will build a battery or buy one but lets just assume 72 volts and I can build to get the range I want.

I weight 250lbs and my bike may tip the scales at 75-100 lbs fully dressed depending on how much "beef" I add.

The range I can work out and buy/build a battery accordingly.
My only real question is; can I hit 45-50mph with a 3000 watt motor given my total weight?

Well after a little more research I see that some people are hitting 40-45 mph with the cyclone on some lighter bikes using only 52 volts.
I suspect that with 72 volts my 45-50mph goal should not be too far out of reach.

I think I am going to step up the battery to approximately 20AH but other than that I am sticking to my original plan.

I will be meeting with my bike frame builder friend over my long weekend to discuss frame geometry and construction.

If you can believe it I am trying to build this cycle on a budget.
I may regret it in the end but I will likely run some Chinese forks and shock as well as cheap hubs and wheels.
If they suck then I will source some used better parts and should not be out too much unless the parts fail catastrophically and I lose a limb or my life.
I will start out slow and see what the parts are made of.

I am going to focus spending the money on electronics and the battery.

So pretty much I answered a lot of my questions on my own but if anyone has any questions or concerns feel free to chime in.

I used to be 250lbs with a 110mph+ ebike and broke bicycle rims, spokes, tires, and forks, sometimes all in a single day. If you ride high speeds on smooth terrain only then good bicycle parts hold up usefully well at motorcycle speeds (except bicycle brakes fade on tracks).

Yeah when I would be going 45 or 50 it would be on smooth roads.
If I ever get it off road it would be slow speed and by off road I mean the occasional two track or field.
Probably nothing super gnarly.
Brakes really are my only concern at with the bike parts.

I have a set of 203mm rotors I intended to run but, as many know, they are really thin and just don't have the heat capacity.
I have been seeing some info about the dual rotor set ups that that are starting to pop up in some of the downhill groups these days.
I found a fork with a dual brake set up so now if I can find a decent budget dual rotor hub I may give it a shot.