This works much like the air filter tip, and because we love to yell, we're going to scream this: CHANGE YOUR QUAD'S OIL ONCE IN A WHILE, WOULD YA? Sheesh. Just like the air filter, oil collects junk and gunk. From little metal shavings from engine wear to dirt and debris, the oil is a breeding ground for a break down. And if you're playing in puddles with your quad, you might have a nice little water and oil mixture going on there, and you know what they say about oil and water: they don't mix. So, at the end of your riding season (if you're a seasonal rider), replace the oil. Or, you can do it in the spring (but we prefer our quads to have fresh oil in their bellies while they wait out winter). If you ride your machine in the cold months, change the oil to the appropriate weight for colder temperatures. And in the heat of the riding season, change the oil if you get in too deep with a body of water or a mud pit. If you're racing your quad, it's not unreasonable to change the oil after every race. Basically, the point we're trying to get across here is change the oil in your quad at least once a year, and do it more frequently if you're a frequent rider.