I was able to build a motorized fatbike for about $500, sourcing all parts from amazon.com!

I have since rode the moped over 100 miles, and counting.

This thing is a blast, and was incredibly simple to build.

I wanted to share how I did it in case any of you Steemers want your own. The bikes top speed is somewhere around 27mph on level terrain, although I've reached close to 40mph down large hills. The tank holds about 3/4 gallon, and fuel economy is around a whopping 100 mpg!!!

What you will need:

Mongoose Dolomite fat bike $233 http://a.co/cbZ31EF
Seeutek 80cc Bicycle engine kit $119 http://a.co/5t8FJMa
3.5 inch tire for the rear: $35 http://a.co/9yuo7p5
Three U-bolts from your local hardware store: $5

You will also need a basic bicycle tool kit, including a chainbreaker, as well as a rotary tool with cutting wheels, and a few basic hand tools like adjustable wrenches and screwdrivers. I added aftermarket parts like a seat, handlebars and lights, but they aren't required to get started.

The first step was unboxing and assembling the Mongoose Dolomite. This is pretty straightforward, following the included instructions.

After unboxing the engine and test fitting the parts, I realized two parts needed modification, the rear engine mount and the drive sprocket. This is because the kit is designed for standard bikes, not fat bikes. But no worries, I was expecting a challenge. The engine mount was an easy affair, I simply ditched the rear mount altogether and combined three U-bolts to hold the motor against the bike frame where I needed it. The sprocket was a bit more tricky, as I had to estimate how much i needed to widen the hole for the hub, and then somehow cut it with a rotary tool. This took some time, but I was able to get it to fit true by eyeballing it and slowly refining the hole with a grinding wheel.

After that, I simply followed the instructions included in the engine kit. The final challenge I encountered was the drive chain rubbed on the back tire a little bit. This was easily solved by swapping to the slightly narrower tire I linked above. Standard installation time is approximately 4-6 hours for a somewhat handy person, a bit longer if tools aren't your thing... Anyway, I hope you found this helpful, and good luck with your motorized bicycle build!