I think they use different measurements; one company by diameter and one company by flow. What kind of Keihin? I've had a few CV types and those tune the same no matter what they're on.
Originally Posted by supershaft
The bottom line is that unless you have a too lean main jet. Jet needle adjustment will not effect the main.
Jet needle height adjustment affects the flow, main jet restricts the amount. Bigger mains allow more fuel into the needle jet, smaller mains allow less. Higher needles allow more fuel flow, lower needles allow less. A low needle and a big main or a high needle and a small main work pretty much the same until you reach WOT. Such an easy concept, even a super tuner such as yourself should recognize this.