Cv Carburetor System; Carburetor Function; Vent Systems - Cv Carburetor; Mikuni Cv Carburetor Operation - Polaris Outlaw 500 Service Manual

CV CARBURETOR SYSTEM

Carburetor Function

Carburetor Component Function
Main
System
Components
Inlet Pipe, Needle
Float System
and Seat, Float,
(Level Control)
Float Pin
Passages in
Venting carburetor; vent
lines to frame.
Choke Lever, Cable,
Plunger, Return
Starter
Spring, Carb
(Choke /
Passages (Starter
Enrichment)
Jet, Starter Bleed
Pipe).
Pilot Jet / Passage-
ways, Pilot–Mixture
Screw with Spring
Washer and Sealing
Pilot
O–Ring, By-pass
(Idle System)
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.
Main Main
Function Affect
Maintains specified
fuel level in float
All systems; all
chamber
throttle ranges
(carburetor float
bowl).
Supplies
atmospheric All systems; all
pressure to float throttle ranges.
chamber.
All throttle
Supplies additional ranges.
fuel air mixture Greatest effect
necessary for cold at low throttle
starting. settings and
idle.
Mainly idle to
Primarily supplies 1/4 throttle.
fuel at idle and low Minimal effect
throttle positions. after 1/2
throttle.
Supplies fuel at
1/4 to full
mid–range and high
throttle.
throttle settings.
FUEL SYSTEM / CARBURETION
Vent Systems – CV Carburetor
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.

Mikuni CV Carburetor Operation

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
Atmospheric
Pressure
Atmospheric
Air inlet
Vacuum
Slide
Venturi
= Low pressure
4.5
4