How long to break in a new engine?

depends on what engine it is normally for first five hours dont ride over haif throttle, keep the load down and vary your speed, the next 5 hours keep it under three quarter throttle it takes a min of 10 hours to break in a motor some go as far as 15 hours , i would be changing your oil as well after the first 10 hours of use and refill with correct grade and dont overfill remember a carefull run in period will extend the life of the motor up to 3 times longer than a motor that was pushed hard from brand new dont over rev it allow it to slowly bed itself in and youll be rewarded in years to come