MOPED ARMY

in a nutshell raising the port raises the power band, stock puch cylinder powerband is from like 2000-4000 rpm, that kit is probably ported out of the box to 6000-8000 rpm

i'd suggest reading Jennings '2 stroke tuning' as a primer into the world of tuning two strokes. Bell is also a good read and more current, its higher level stuff in some instances but a novice can still follow it pretty well.

If you're going to buy one, I prefer the Bell book.

Really important to consider the effects of the exhaust, specifically the expansion chamber. As the piston is moving up, the return wave from the expansion chamber will hit the port and hold the fresh charge in the cylinder, effectively increasing the volume of the cylinder. These two strokes are fundamentally simple but when you start looking at the wave action inside them, they get complex quickly.

How can the bings still be used with kits and aftermarket pipes? The only adjustments to such a wide range of demands imposed, beyond the very specific ones the oem bings were designed for, are needle slots and intake restrictors. Isnt any attempt to match them with different cylinders and pipes just badly limited from the start? (edited)

You can download it here for free

OP cool thing to notice is the amount of time the exhaust alone is open, this is known as blowdown. More blowdown requires a bigger hit from the pipe but when matched properly is the reason 2 strokes are so damn sweet compared to a 4 stroke.

12mm Bing is fine, 14 if you have it, you can tune with changing the Needle and Needle Holder, if you don't change them around you can't use an Airfilter that flows more than Stock.