replaced piston and cylinder on 440 stihl

[Bolie]

any particular breaking in tips? this is a first for me and it cranked. any info will be greatly appreciated!!!!

Bo

[Al_Smith]

Set the carb just slightly rich for a couple of tanks .The saw will tell when it's ready by the increased compression .Then lean it out til it's right and run it like you stole it . ;)

[CTYank]

It's generally considered good practice for the first 10 hours or so to:
add a little oil to the mix (40:1 vice 50:1, say)
avoid long full-power runs (give it fast-idle breaks)
give it a short warm-up before full-power, and a cool-down before switching off
richen high-speed mix a bit beyond optimum (see below)

at all times: use good-quality fuel & oil; clean chips & dust from cover & fins. Shake mix well before pouring.

Optimum H carb adj.: engine 2-strokes under load in cut, just 4-strokes when lifted (load reduced)

[nmurph]

Just put the mix in it and run it.

[Clam77]

+1 on that.