There are two schools of thought on breaking in an engine.
There are those who say to baby the engine until the first 1000 miles, to be sure you don't break something.
And there are those who say there is a specific technique you can use that will ensure the engine is properly broken in, but without abusing it in its infancy.
I subscribe to the second train of thought, as it makes sense. It goes something like this:
Limit idling periods to under 2 minutes at a time, except for initial warm-up.
Don't go to WOT for long stretches until you hit the 1000 mile mark. Keep it to a maximum of 50% throttle for long stretches until you hit 300 miles, and 75% throttle until you hit 1000 miles. But DO go to WOT when taking off from a dead stop, until you hit cruising speed.
When decelerating, snap the throttle closed, don't 'throttle down' to a stop.
When you're taking off from a stop, hit the throttle hard up to cruising speed. The added pressure in the cylinder will force the piston rings out against the cylinder wall, ensuring they wear to a flat surface that has greater sealing capability, longer life, and less oil usage. If you 'baby' the engine, your rings won't seat properly, they'll have a more rounded profile, which will wear them out faster, have more blow-by, and cause more oil usage.
http://www.mototuneusa.com/break_in_secrets.htm
