Re: new to this, hoped for some advice...
Hi 13013 -
Welcome! You will learn something new every day as you read more. MY input: I disassembled an 80/66 cc engine to its last components. It is my "experimental" engine. For its price (cheap), I have no complaint. The insides were clean, no loose metal shavings. The engine was not CNC machined as a really expensive engine is. "Close-fit" casting is the norm for these engines. Because the internal rotating crankshaft is not balanced, the engines shake/vibrate a lot. That vibration energy is absorbed by the bike frame and the rider. Aluminum frames hold up for time (months to years) which no one can predict. Steel frames tend to hold together much longer. The clutch plate engages and disengages just like a manual shift vehicle's clutch when the clutch lever is moved in and out. Not high tech, but it works. The engine maker assumes your fame tubes are about one inch in diameter. If your bike tubes are significantly larger, one way around that is to get a yard sale bike. Make your errors and learning curve on something inexpensive. I got hold of a bicycle maintenance manual and learned how to completely rebuild axles and the bottom bracket. A bike shop "tune-up" does not include this. Using "mainstream" bike frames will get you on the road faster. Then you can take everything apart and put it all on your next frame of choice. I am a strong advocate of using the best head helmet before you start your first ride. Your future income far outweighs the puny cost of the most expensive helmets; don't go cheap here. My lady friend crashed in her first mile. Her helmet saved her from serious injury.
Read and learn; there is a lot of experience here!