Hey guys I recently picked up a 700 king quad with 589mi on it. It runs strong with no issues but I have noticed a small stumble when your on the gas, let off and then get back on it quick. It almost sputters for a second then goes back normal. I also notice it when I'm climbing a rocky trail fast and the bars move and make my finger stab the throttle. No clue on what it could be, I put a new spark plug in when I bought it just out of habit. (Always do it when I get a new machine) any ideas???