unwritten rules?

#1
My young hunting buddies were not around during the mini bike craze. They were somewhat impressed with my "jimmy gote" I built, but were saying I should have just bought a junk dirt bike, used those wheels and forks, and frame, and rebuild that motor or just buy a real dirt bike. I tried to explain the concept of using off the shelf, time period parts. But then the use of Honda clone motors, Lifan motors, disc brakes, LED lights, came up. Wondering, where is the line drawn? If you had to explain the "rules" how would you do it? does this site have a list?
 
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