My raptor won't idle unless it's a high idle. At regular idle it'll backfire through the exhaust and carburetor and shut off and I'm pretty sure I saw flames come out the exhaust when I was revving it to keep it running. I've cleaned the carbs but I do need a new air filter (currently using socks over the metal cone filters until my new one ships) it runs great when on the gas and does fine through the gears