Revelstone, pb engines are bargains, compared to $275+ Robins/Hondas/Mitsus/Tanakas. Ya just have to fab the throttle and tank.
Right now I have a stock pb and a 10hp(supposedly)pb engine awaiting a donor bike. The HP one is bolted onto a Staton gear chain drive box, awaiting a donor bike. I'll prolly get restless, and fit it to the friction drive on my cruiser bike.
Rack mounts are much easier to install that engine, especially with Staton products.
5-7