Proper break in of your pit bike is crucial. We have heard a million different ways to break in your new pit bike and our method comes from years of trial and error. We won’t go into our entire method here but you can refer to our tech support section of our website for details on the actual process: http://www.orionpitbikesales.com/garage.htm
From our experience the slower the better seems to be the best policy. We usually recommend the heat cycle portion 3-5 times minimum and then take it easy for the first tank of gas. We have noticed on the bigger bore pit bike motors, like the 140cc and the YX150cc, even 5-7 cycles and only 1/4 throttle for the first tank actually makes for a more powerful and snappier motor. Another side effect of a longer break in period that we have noticed is less valve adjustment. Traditionally a valve check & possible adjustment is needed every 10-20 hours. We have had some pit bikes that have had the longer break in period never need adjusting.
So the break in of your pit bike is not the most fun process and takes time but from our experience it could be well worth it.