I can say that I have an extreme lean condition on my quad. I started it, and I ran inside to get something real quick. I was only gone for less than a minute. When I came back outside I saw something glowing red from the front of the quad. It was my head pipe. It was a nice and shiny glowing red. By the time I got to the quad, the redness had spread to about 5 inches down the length of the pipe. I shut it off when I got to it. This all occured in just over 2 minutes. Wouldn't you have to say that this machine is running EXTREMELY lean? It was only on for 2 minutes!! My question is, why would the quad just now start running extremely lean? what could have changed? I have no mod on the quad at all. I also run regular gasoline in it. The quad also sputters if you hold the gas down. It coughs, sputters, and sometimes misses. But if you hold it down a little bit farther, it revs fine. Also when you first start it, you cannot even touch the throttle or the machine will die. Is this also from it running lean?