Best and most "linked too" article on this subject is MotoMan's "Break-In Secrets"

Another along the same lines, by the North Texas Norton Owners Association "New or Rebuilt Engine Break-in Procedure"

This method is not just restricted to rev-heads. Read the CASA FSA 2002 Sep-Oct article - a reprint of the AOPA Pilot magazine article
(This article is no longer available on the CASA website, but has been archived by the National Library of Australia)