Apex - built motor break in


Mar 9, 2020
Just did JE Pistons and Carillos. I like to heat cycle my stuff 2x and run it hard with a varied throttle position but I would like opinions from those that run a built motor
Oct 8, 2009
On a fresh rebuild you should be relatively gentle for the first 25 miles or so cycling the throttle. You take some short bursts but try to keep the rpms down. You want to make sure the new surfaces get to know each other before you start to push it. After you know the build is good and ready for more, you want to start doing pulls where you accelerate down trail for a short pull and let it fully decelerate, coming down on compression. A long deceleration after a hard acceleration is what really helps seat the rings. Dont just hold it wide open or your rings won't seat properly; you will get excessive blow by; and you will make less power in the end. Do the accel-decel processes for as long as you can stand it. Obviously, you need to be able to stand riding it through the process, so do some riding too.

Once you have 3 or so rides doing that, your probably okay to go. That will be roughly 200 miles of backcountry riding or 300 to 400 trail miles. Remember the hard decel for a long duration is what you are after, not the acceleration.
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