Thanks thats great info, I was thinking of getting the q-matic transmission from EZMotorBike and getting the 79cc predator from HF. What else do I need, I assume a mounting kit?
Correct, you will need to make or buy everything else to mount it and make it go.
You will need to make a base plate and mount for your bike, an exhaust pipe, a back sprocket with mount, a chain tensioner, a throttle with kill button, a gas tank, new wider bottom bracket and crank arms, and buy a bike big enough to fit it as the Q-matic and 79cc are a very wide combo.
I used a 29" Micargi Fatal Love for my 79cc Pred with Q-matic build.
http://kcsbikes.com/topic.asp?TOPIC_ID=648
That's a Wizzer tank on mine, and I put dual C-brakes on it to aid the coaster brake, a V-brake or Disc front fork would be advisable as it does scoot along pretty fast.
I like the HS 142 49cc engines and 4G myself.
Bicycle-Engines.com has a complete 49cc 4G kit for $300 which is what just the 79cc and Q-matic costs.
I really like shifters best though, performance gain via gears is tough to beat to the point of designing the new 10G KCK long shaft transfer case.
Check out this 7-speed Fito.
http://kcsbikes.com/topic.asp?TOPIC_ID=861
It would be better with an internal 3-speed hub and shock front fork like this 2-stroke Fito I'm building but regardless a comfy safe machine that looks cool.