Hi Guys, I have a few q’s on carb setup Alot of people here in australia run lean needles and rich mains. (ie k22 266 and 168) but the tendency in europe is to run rich needles and leaner mains. ie k8 needles, 140-150 mains, etc Why is that so? Is it simply better that way, or is it a characteristic of circuits.
Also, if the circuit has long straights as opposed to one with twisty corners, do you go jet richer bottom or tops? Do revs make a difference?
The tip of the needle is included in the math when calculating the annulus of the tip/main jet area. This area (annulus) meters fuel at wide open throttle. At any position other than WOT, the taper/main jet/atomizer meters the fuel.
once it’s full throttle, don’t you see the huge difference between 132 and 162.
Remember the setup you used for an example is pretty close to the same as far as main jetting is concerned. One needle has 1.50mm tip the other a 1.80. but the different main jetting compensates for difference in needle tips.