I have recently completed a top-end rebuild on my son's 1992 YZ125 and went searching for a break-in/run-in procedure. It seems that there are many and varied opinions ranging from the Yamaha "pull the head off a few times and check this and that" approach to the "just get on the thing and ride" approach. I am after some kind of consensus on the procedure (I expect there isn't one) or at least what NOT to do. This is what I have so far: 1. Use the normal ratio of premix as more premix equates to a leaner mixture and therefore hotter running. 2. Two warm-up/cool-down cycles at or near idle. 3. A ten minute run at no more than 1/4 throttle with minimal load on the engine, followed by a cool-down. 4. A ten minute run at no more that 1/2 throttle with varying but moderate load on the engine, followed by a cool-down. 5. Now go for it! Any help would be appreciated.