We were just given a sunl sla-90 mini. The only thing that was wrong was the brake pad came off. we fixed that two days ago when we got it. Its been starting and running......till today. We started it ran it for about 20 min. shut it off. Tried starting it 20 min later, wont start then backfires. we checked all the connections, battery, fuel, oil, has spark, etc. We try to start it and nothing. we smell gas as if its flooded. Try to start it a few more times and nothing but backfires again. Please help. 7 year old was so excited, and now crushed.  

install a new spark plug ngk c7hsa, then do a valve adjustment. set both valves at .004  

We went ahead and brought it to shop. It was the spark plug and the teather (think thats how you spell it) We had got the e-mail after we brought it. It runs better then when it was given to us.....purrs like a kitten. This is out first atv or should I say kids...lol. We hope to get one soon for ourselves and another for the kids as well....for my girl. Thanks for the info and I'll remember to change the spark plug before anything next time.