ORIGINAL: JohnBuckner
Those types of generalizations can be so inaccurate that in many cases they are wildly wrong. As said by many previous posters such a chart can be useless. The rules of thumb of just ten years ago really have no bering on a lot of what is out there now.
The performance distinctions between the two types of operating cycle are disappearing. There is at least one line of four strokes out there that arguably in the various displacement catagorys offer more useful power than many of the similar displacement two strokes.
John
I have tested my OS 2 stroke 120 size (AX series) and have seen a buddies used YS 120 size, both with a 16 x 8 APC prop tach numbers are around 9,000.
It is very real to me that both kind of engines are improving, and it seems to me that even that 4 strokes have lower RPM numbers, they have an invisible torque which is in need on some emergency cases or for some 3D maneuvers.
Just a few years ago a 120 size 4 stroker engine was a very heavy and big engine,
Now the manufacturers have improved their efficiency and they are selling now those high power engines in a small lighter sizes.
I love all my 4 stroke engines but it is a truth that there are now at the market some great 2 strokers which can handle bigger props as the 4 strokers were doing for years.