My break in routine is similar to Grizzly Wizzards, but without the idle time. Letting a new engine idle is not best for cam break in. I try to purchase a NEW ATV that is still in the crate at the dealership, and not an ATV that has been used for demo rides. I start it at the dealer just barely long enough to load it on the trailer and take it home. Once home, I do three heat cycles with the engine. A heat cycle means I start the engine and ride it around slow at less than 25% throttle, continually varying the throttle, for five minutes, which is just barely long enough to bring the engine up to its normal operating temperature. After each heat cycle I let the engine cool to room temperature (usually over night). After the three heat cycles are completed I will take the ATV on longer rides, continually varying the throttle, but keeping throttle to less than 50%. At five engine hours I change the oil and filter, and put in the best synthetic oil I can find. After the first five engine hours I will allow very brief throttle applications up to 100%, but only VERY briefly, and I try to keep sustained throttle application to less than 50% throttle. Once the engine has ten hours on it I change the oil and filter again, and will then ride it just like any other ATV.