Talk about break in time. I ran my new 2100/240 hard right away with husky oil and high test gas. They ran awesome from the get go. Note, after running stock craftsman sears saws I was in heaven cutting with the huskys. Soon after the 266SE joined the other two huskys.
Now fast forward my son hooked us up cleaning out big trees from a saw mill that wasn’t quality lumber. I purchased a new husky 385xp, a new 575, a new 353. I was told to run high test gas, and go easy while breaking them in. Only use husky two stroke oil in them because of the tighter tolarences. We cut 20 cords of firewood. As soon as we hit 20cords both saws turned on the after burners. At first they weren’t the same husky saws as my older husky saws were. They just weren’t cutting right. Once they were broken in they ran awesome.