Question about motor

2 replies to this topic
  • Auggie

Posted July 09, 2011 - 02:17 PM


My 426 is done after installing new upper and lower ends, how should I break it in? I was going to just ride it light one ride, but where my cylinder was replated they said to move the main jet up 4 sizes before starting? What works best?

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  • grayracer513

Posted July 09, 2011 - 04:35 PM


Leave the main jet alone.

Start it, be sure oil circulates, and that everything looks good, ride it easy for 5 minutes and shut it down. Let it cool for a few minutes while you look it over, fhen start it and run it for about an hour at about 80% of its capacity. DON'T baby it, but don't thrash it, either. At the end of the hour, change the oil and call the matter over with.

  • jratcliffe3

Posted July 11, 2011 - 01:18 AM


Main jet thing sounds like it comes from a 2 stroke person, I can't see any benefit it would/could give you on a 4 stroke.

My break in is ride less than half throttle for 15-20 mins, then let it cool. Then ride it like normal, change oil after first hour.

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