I agree with you 100% not every single engine with pipe is tuned the same way.

Here is a step by step guide how to do it.


Attach the header at its full length, with the silicone coupler and the pipe. The front end of the pipe should be about 1 mm from the rear end of the header, with no contact.
Any length within the coupling is an integral part of the 'tuned
length'.
Firmly attach the tuned-pipe, so it is not blown back by its own
pressure waves...

1. Open the high-speed needle 1 turn from the last no-pipe running
position and start the engine.

2. Adjust the high-speed needle at full-throttle, for the highest RPM
(without any sagging). Write down the RPM! Don't remember it, just write it.

3. ***Make sure that if you close the throttle to idle and then open it again, the engine returns to the same top RPM it had achieved! This must happen without you having to 'pinch' the fuel-line, or to touch the needle again.

4. Shut the engine down, remove the tuned-pipe and coupler and using
the tubing cutter, remove 5 mm off the rear of the header.

5. Keep the piece you just cut and de-burr the end of the header, so it is smooth, with no shavings, or flow obstructions.

6. Reassemble everything, pushing the tuned-pipe forward the header,
until they are again 1 mm apart. Repeat from '1' and again note and write down the RPM. It should be higher than it was earlier. It could only be slightly higher. Make sure '3' occurs! It is one of the criteria that can determine that you are done.

If the RPM is not increased after the last cutting and/or the engine
will not return to the same RPM, upon opening the throttle from idle to full (meaning it has become too short), you are basically done!
Insert the last piece of tubing you have cut off the header, into middle of the silicone coupler and reassemble the header, coupler and pipe.