I recently purchased a raw 66cc bicycle engine kit and have put around 200 miles of use on it. I was riding the other day with my friend and the engine backfired once and the bike slowed to a stop and cut off. I tried to restart it but it was as if the piston was not getting any fire. So I bought a new spark plug and tried it but it still didn't work. I then tried my friends spark plug that we knew was identical to my previous one and it still didn't work. It's hard to explain the problem but when i drop the clutch the engine turns over as long as I pedal but it won't kick on. When I give it gas it sounds like it is trying to get going but can't almost as if its flooding but I checked carburetor and it was fine. Not sure what the problem is can anyone point me in the right direction?