The key to proper break-in of a new top-end is to put it through several gentle heating and cooling cycles, to relieve the pent-up stresses in the piston left from the manufacturing process.
Start the engine, and let it warm up, using small throttle blips to keep it from loading up. No high revs, and no riding. After 5 minutes or so, shut it off and let it cool completely.
I use Wiseco forged pistons, so I usually repeat this a second time.
Start the engine and warm it up, again with no high revs. Ride the bike gently, using no more than 1/4 throttle, and vary the throttle position constantly. Don't put a heavy load on the engine, like climbing a steep hill or something. Do this for 10-15 minutes, then shut it down and let it cool completely.
Repeat again, using no more than 1/2 to 3/4 throttle. Let the engine cool.
Repeat one final time. After 10-15 minutes, give it a couple of full-throttle runs through 2 or 3 gears to ensure the rings are fully seated, then shut it down to cool.
Re-torque all head and cylinder bolts, check over everything for tightness. Now you are ready to rip!:cool:
Thanks spanky250, that's great advise. It is very similar to what one of the local dealer guys told me. It feels great to have the bottom end back, and to have great power for hills and weelies. STAYING IN IT- with the '92 KDX.