Hey yall, I just bought a bike off Craigslist that has a 66/80cc motor. It was used a few times before purchase. I rode the bike 50 miles to get home, and it rode fine most of the way, except there was a few minutes where it shut off on me and I coulnt get it started. I messed with the wires from the coil and it turned back on. I finally got home, and it worked fine the other day, but again the engine would not start, I pulled off the spark plug wire and a gold threaded piece came out with it. I tried to screw it back in for about an hour but it would not catch. I looked inside the cap with a flashlight and saw that the threads inside were almost smooth. I went to the local lawn mower shop to see if I could get another cap, but they want to charge me $14, I looked online and found them for $1.99 on Amazon, so I ordered 1 of them. Hopefully that will take care of the problem. I also noticed some burn marks on the rubber around the ends of the coil wires. I dont know what that is from. Is there a way to test the coil to see if it is still operational?? I am so glad I found this forum, because I am slightly mechanically retarded so I will probably be needing alot of help. Besides that I am excited to have my new bike and look forward to putting alot of miles on it without worrying about emptying my wallet in the gas tank.