Number 1 is at the blunt end, #5 (or #6 sometimes) is on the pointy end. Yes you do understand correctly.
Hey! I can be agreeable, can't I?
re: 220 starting point?
First...a repeat..again, even. No one can jet by mail..or email for that matter. All bikes are different. Oils are different. They way you gapped your plug will make a difference...etc. etc....
Generally speaking an OEM 'H' 220 will be
somewhere around 142/145 with a 42 pilot and the needle on clip-2. A pipe will add one to that main...make it 145/148.
IMO (THAT never works in jetting somebody else's bike
either!) you will probably end up one lower on the pilot (a 40) and the Kaw needle is a waste of your time altogether. Less diameter, a later starting slope
and a sharper slope (more º) will work better.
Here's a pivotal point on needles. Well...it was 'fer me!
L1 is the 'straight' spec of a needle. First off...it's not at
all just the part of the needle that is
straight! That's logical, ain't it? It is the length of the needle from the blunt (clip) end to the place on the needle where its diameter is 2.515mm. So...part of any L1 is going to include a tapered part of the needle.
Where the different slopes matter (well, one place anyway) is this: The more slope (steeper angle, more ºs), the sooner that 'magic number' (2.515) will be reached! Take an 'A' needle and a 'C' needle with the
same L1 measurement: The 'C' needle taper will
start further down the needle than will the 'A'. The faster the slope, the sooner you get to 2.515, so the
later you start heading there!!
Aha! All of a sudden it is very evident WHY a different slope of needle matters in the lower throttle ranges, 'eh? That 'A' needle has a leaner taper, but it has a
richer bottom end!!
Isn't that cool!
Of course it is!!!
An anecdotal aside..that's why the 'A' needles in your carb get you a loaded up plug on a long downhill (idle) run. The taper is out of the needle jet even with the throttle closed! You hit the gas after that downhill..and all you get is 4-stroke burble!!
A 'B' (OEM needle) isn't as bad, but it's close! That's part of the, 'Help me!! I keep fouling plugs!' whine 'ya hear all the time on this and other boards.
One more slight aside....the vacuum created by a venturi doesn't
suck the fuel out of the carb bowl. Atmospheric pressure
pushes the fuel to the lower pressure. Small matter...but it
does matter!
Good write-up on needles and stuff, Rhodester! You KNOW it was simplistic...'cuz it
made sense to me!!