Originally Posted by nitrodude

4 hours don't do anything, and raising the RPMs doesn't do anything either. You have to think that when you heat it up it expands, making it easier on the rod and making the piston/sleeve fit slightly looser(the piston expands less than the sleeve) I do mine for 10-12 hours, 1st hour at 210, then I lower the temp to 190 and let it run overnight. Then I do one bottle rich(lots of smoke and very little power), let it cool. I start the next bottle where I left off with the previous one, but I lean it a bit each tank, by the the last tank the motor is almost on race tune, but 2 -3 hours rich, and letting it shift. I do one more bottle at that setting. Then its race ready, I haven't had any motors get scratched or heat spotted, as long as that procedure was followed.-