Polaris SCRAMBLER 50 Service Manual page 61

FUEL SYSTEM/CARBURETION
inside the needle jet.
Needle Jet
THROTTLE OPENING VS.
FUEL FLOW
In a 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 jet. The main jet
therefore has greater control over fuel flow.
Small
Clearance
Closed One-half
Throttle Throttle
Main Jet
Medium Large
Clearance Clearance
Full
Throttle
THROTTLE SLIDE
The throttle slide controls the rate of engine air intake
by moving up and down inside the main bore. At small
throttle openings, air flow control is performed chiefly
by the cutaway. By controlling air flow the negative
pressure over the needle jet is regulated, in turn
varying the fuel flow.
Throttle Valve
Engine Side
Higher cutaway number = leaner mixture
The throttle valves are numbered 1.0, 1.5, 2.0, etc.,
according to the size of the cutaway. The higher the
number, the leaner the gasoline/air mixture.
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 jet. The number on
the jet indicates the amount of fuel CCs which will
pass through it in one minute under controlled
conditions. Larger numbers give a greater flow,
resulting in a richer mixture.
Main Jet
Hex Style
Main Jet
Larger Number = Richer Mixture
Main jets are screwed directly into the needle jet base.
Air Box Side
Cutaway
3.7