2008 Polaris ATV Predator 50, Sportsman Outlaw 90 Service Manual, Page 94Get this manual
FUEL SYSTEM Throttle Opening vsFuel Flow
In full throttle condition the cross sectioned area between the jet needle and the needle jet is larger than the cross sectioned area of the main jetThe main jet therefore has greater control over fuel flowSmall Clearance Medium Clearance Large Clearance
Main Jet
When the throttle opening becomes greater and the area between the needle jet and jet needle increases, fuel flow is metered by the main jetThe number on the jet indicates the amount of fuel CCs which will pass through it in one minute under controlled conditionsLarger numbers give greater flow, resulting in richer mixtureMikuni Main Jet (50cc)