System Function - Mikuni Cv Carb; Vent Systems - Mikuni Cv Carb; Operation - Mikuni Cv Carb - Polaris Ranger 500 2x4 2007 Service Manual

CARBURETION SYSTEM

System Function - Mikuni CV Carb

Carburetor Component Function
Main
System
Components
Float
Inlet Pipe, Needle
System
and Seat, Float,
(Level
Float Pin
Control)
Passages in
Carburetor, Vent
Venting
lines
to frame
Choke Lever,
Cable, Plunger,
Starter Return Spring,
(Choke/ Carb Passages
Enrichment) (Starter Jet,
Starter Bleed
Pipe)
Pilot Jet/
Passageways,
Pilot-Mixture
Screw with
Spring Washer
Pilot (Idle
and Sealing O-
System)
Ring, Bypass
Ports (Behind
Throttle Plate),
Pilot Air Jet, Pilot
Outlet, Throttle
Plate
Main Jet, Main
Air Jet, Main Air
Passage, Needle
Main System
Jet, Jet Needle,
Vacuum Slide,
Throttle Plate

Vent Systems - Mikuni CV Carb

The carburetor float bowl vent lines supply atmospheric
pressure to the float bowl. The lines must be free of kinks,
restrictions and be properly routed. This allows fuel to flow in
the proper amount and prevents contaminants from entering the
carburetor.
4.6
Main Main
Function Affect
Maintains
specified fuel
All systems
level in float
All throttle
chamber
ranges
(carburetor float
bowl)
Supplies
All systems
atmospheric
All throttle
pressure to float
ranges
chamber
All throttle
Supplies ranges
additional fuel air Greatest
mixture effect at low
necessary for throttle
cold starting settings and
idle
Mainly idle
Primarily to 1/4
supplies fuel at throttle
idle and low Minimal
throttle positions effect after 1/
2 throttle
Supplies fuel at
mid-range and 1/4 to full
high throttle throttle
settings.

Operation - Mikuni CV Carb

The constant velocity carburetor incorporates a mechanically
operated throttle plate and a vacuum controlled slide valve
(vacuum slide). The venturi cross-sectional area in the
carburetor bore is increased or decreased automatically by the
vacuum slide, which moves according to the amount of negative
pressure (less than atmospheric) present in the venturi.
A diaphragm attached to the top of the vacuum slide is sealed to
the slide and to the carburetor body forming two chambers. The
chamber above the diaphragm is connected to the venturi area
by a drilled orifice in the center of the vacuum slide. The
chamber below the diaphragm is vented to atmospheric pressure
by a passage on the air box side of the carburetor. A spring,
installed in the center of the vacuum slide, dampens the slide
movement and assists the return of the slide.
Diaphragm
Throttle
Plate
= Air Flow
Low Pressure
From Venturi
Air Box
Pressure
From
Air Box
Vacuum
Slide
Venturi
= Low Pressure