Re: what did you do to your motor bike today?
re: Kestrel. Was it $1000 for a frame and fork, maybe?
If you are serious about motorizing one, get a used one from the mid to late 90s, that will probably take a 700x28 or 32 tire. You will probably have to use metal plates drilled in the center for axle mounting, and prevented from rotating by strapping to the chain stays with conduit straps. (to hold the adjuster straps).
Go with something like That's Dax and a 2 stroke engine, keep it light, because the frame is flexy and not made for racks or cargo or motors. You might have to shorten the Dax drive channel and use a short u-bracket, to lower torque against the chain-stay yoke and seatpost area of the frame. It is carbon fiber, so you might need to mount the u-bracket to the seatpost instead, and put a plug in the seatpost to prevent crushing it.
1" roller Dax Friction Drive and Tanaka 3300 with mods.