hey, I have been working on engines for 35 years, and MY OPIONION is break in is exactly what it sounds like. If something is going to break it will usually happen within the first few hundred miles. there is a purpose to letting parts wear in together.(production tollerances, the assembler who had a bad day, the new machine on the line, ect...) I have found if you ONLY ride at a certian rpm the parts will "seat" themselves to that condition, and when you change that condition it's like your little brother jumping out of your closet. the machine does'nt know how to react. I am a firm believer in varring your rpm's, and tourque load on ANY multi use engine. Now I do not say to drop the hammer on a newly built engine, but hit it for a few moments , and let the parts see whats in the closet (so to speak) As always the best Quality fluids, regular changes, and maintenance are the real key to a dependable engine. I hope Everyone understands this is only MY opinion.