Chainsaw Repair

Generally speaking if you raise the rpm range the port time area open will require some adjustment .In simple terms as the time deceases the area must increase because you can only shove a certain amount of fluid or gas  through a certain sized hole in a given amount of time with a given amount of pressure .

Another thing to keep in mind is with port loop scavenging on a two cycle engine is it starts and ends in atmospheric pressure .It's the differentials of pressures within that complete cycle that determines the flow within regarding pressure changes .--clear as mud --