Best way to break-in new motor

3 replies to this topic
  • Ronnie Mac

Posted September 07, 2003 - 06:43 PM


OK I have read post on ride slow and easy, like the manufact of my bike. Or run it like hell because some guy with a enginering deg said too. So who would you believe someone with a reputation of quality and longivity too up hold like the manufacture or some dude with a so-called deg and the time to post it on a web site??? can you tell me wit facts or just your own speculations. :D :) :D

  • wr400woody52

Posted September 07, 2003 - 07:14 PM


The best answer lies somewhere in the middle. It is all about heat cycles. That is what tempers all of the different metals in your motor to the relative same temper. A heat cycle is best described as bringing the motor and transmission up to operating temperature then letting them cool down completely. If you don't let them cool completely (like several hours) then it isn't a complete cycle. The first time should be the easiest because that is when any ill fitting areas will wear and create heat spots (a bad thing). So that means low loads and lower RPM's but you need to go through the gears and don't forget the brakes they also need to break in. The next runs can progressively get harder in the Load and RPM range. In a two stroke three times to 100% on a four stroke 5 times is very safe. The most important part being a full cycle. We use the dyno for the first heat cycle because it is convienent. It lets us know right there where we can fix it if there are any problems. The hell bent for leather method is good for racers who just don't have the time to wait and they are going to be back into the motor after the race weekend anyway. The super soft and loving method is not agressive enough and can actualy cause some major problems with how hot your bike runs. I am a retired road racer (as of half way through this year) and used to break in two motors every race weekend and several more per year in testing. I have broken just about everything you can think of, I also graduated from AMI in Florida in 1988. I w :applause:ould tell you to take any advice you get for what it is worth (freee!)

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  • Ronnie Mac

Posted September 07, 2003 - 07:35 PM


woody I really injoyed your response. But what do you base your method on. I know guys that ran the piss out o their bike and lasted just as long as mine ( I babied mine)Whats your make-up. :)

  • Junior_Vet

Posted September 08, 2003 - 08:45 PM


I made sure that it running right, and really warmed up well. Then I rode it as much like I stole it as possible considering I'm an old fart who doesn't want to fix it right away. Translation: I rode it hard (WFO) but didn't rev it to the rev limiter. :)


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