Whenever I put in a new piston I start it up and keep it at about 0-1/8 thottle, being very gentle. I let it warm up and then kill it, then let it sit for about 30 minutes or until it cools down, then I do the same thing warming it up. Then I let it sit for 30 minutes or until cool, then I ride it around keeping it at less than 1/8 and low rpms until it warms up again, then I let it cool. Then I ride it around at less than 1/2 throttle and still low rpms until warm, then kill and cool. Then ride it for awhile letting throttle go to maybe full but not keeping it at full for more than a few seconds. Then I let it cool, then I ride it like normal. I usually go through maybe 2 plugs doing all this, but u could just clean them up if they get fouled, then put a new one in when the bike is gonna be rode normal. My method might be alittle longer than other, or maybe shorter. You mainly just want to get it through a couple gentle heat cycles so that the piston and rings can get seated well. Good luck with the new bike, have fun.