don't be a fool and drive your brand new engine around at wot without even idling it!! that's stupid, you'll just stress the conrod, piston and the liner!!
high quality engines like novarossi, sirios, jp rb's etc etc etc are so tight when they are new that if you "drove it like you stole it" without idling it you'de probably cause damage to the conrod. you might not break it then but one day at a track.... with hot weather.... and not the best fuel and BANG! your engine will die.
idle for 3 tanks at stock factory needle settings (or richen top and bot 1/8 to 1/4thj if you are using low oil racing fuel, ie trinity platinum 20%) WITH the fuel you will use for racing. don't go mixing and matching crap. use good quality degummed fuel.
then drive it for another two tanks at max half throttle. always make sure smoke comes from the pipe.
next 2 tanks start going a little harder. make sure your plug matches the weather conditions.
Originally posted by popsracer
3 tanks idling NO Driving, rich mixture. Allow to cool down between tanks (1-2 hrs).
Tanks 4-6 DRIVE around varying the throttle, SHORT (1-2 secs) bursts of full throttle are OK. Re-adjust tuning as necessary.
By tank 6+ you should be able to tune for maximum power. Try keeping your engine temperature in the 220-240F range. It will usually take about 9-10 tanks of fuel for the piston and sleeve to fully be broken in.
*NOTE*: ALWAYS turn the flywheel so the piston is at the bottom of the sleeve when the engine is cooling down. If it cools down at TDC, the piston can become stuck in the sleeve and damage can result from forcing it down. Once the engine is completely broken in this will no longer be a concern.
These proceedures have always worked well for me and my engines are lasting 1-1/2 to 2 years and are VERY fast.
Don't forget to use after-run oil at the end of the days running.