Yes, the cvt was <$80. The Honda gx200 was free! A neighbor had a bad pressure washer pump and was throwing the whole thing away. I ended up making the bike for free. Long story, but I bought everything I needed with money I made from roadside finds. Weedeaters, leaf blowers, etc.
That mount kit would be of little use with the HF 79. The only thing you might use would be the sheave (the thing the belt turns on the rear wheel). If you want to use a sheave, they're sold separately without having to pay $400 for a kit. I forget who makes it, but there is a HF 79cc jackshaft kit avaliable. I'll see if I can find it.
(Edit, I found it)
AGK sells them, and you can find them on ebay or gasbike.net. Get you a mounting plate for the engine, a rear sprocket adapter, some 41 chain, a gas tank, and a twist grip throttle, and you'll be set. A bike with GOOD brakes are a must. (Coming from the guy who only has a rear coaster on his 196cc bike)