Have been searching for this answer for a while, typically I look for an answer & give-up when nobody can provide one but this time I'm going to learn the truth!!

For chainsaws, weed-eaters etc, lil 2-stroke engines that get their lube from the oil mixed-in with their gas, for these lil engines is backpressure at the exhaust-outlet of the engine ALWAYS bad?

Removal or piercing of mufflers is incredibly common-fare amongst tree climbers' chainsaws, every last one of mine has modified mufflers and air-intakes, but am working on a new saw that is very special and, in doing its mods, I really gotta learn whether ZERO back-pressure (and air-intake restrictions) is the true-optimal, I mean I know with cars you have the exhaust gases scavenged &re-used but that's not the case on these lil 2-strokes, but what I cannot discern is whether or not optimization of the block's power would be with or without ANY backpressure at the exhaust-outlet port, in-practice it seems this way but want to verify it, thanks a TON for any help getting to the bottom of this!!!

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    I'm by no means a 2-stroke expert, but it would seem to me, the people who designed the 2-stroke engine in your new saw probably are. If you start putzing around with the exhaust circuit of your saw, you most likely will see negative effects in how it runs. I read this article which might provide some insights into the exhaust on 2-stroke engines, which include scavenging and taking advantage of sound waves within the exhaust. – Pᴀᴜʟsᴛᴇʀ2 Jun 21 '20 at 14:54