2001 Polaris SLX, PRO 1200, Virage TX, Genesis, Virage TXi, Genesis i Personal Watercraft Service Manual, Page 139Get this manual

2001 Polaris SLX, PRO 1200, Virage TX, Genesis, Virage TXi, Genesis i Personal Watercraft Service Manual, Page 139

CarburetionExhaust 2001 Keihin 40mm CDK Carburetor System Overview The Keihin CDK carburetor is float-less diaphragm typeSeveral
arm in the fuel chamberThis reduces pressure on the inlet needle and allows it to lift more easily off the seatWhen the engine
is running, pressure in the carburetor venturi (and therefore the fuel chamber) is less than atmosphericThis increases the
effect of the atmospheric pressure on the diaphragm and lever and overcomes spring pressureWhen the lever return spring pressure
is overcome by these forces, the needle lifts off of the seat or "pops off", allowing pressurized fuel from the fuel pump
to enter the fuel chamberFuel inlet needle "pop off" pressure is influenced by many factorsAtmospheric pressure, venturi
low pressure, the amount of spring pressure on the control arm, and fuel pressure from the fuel pump all have an affect on
operating pop off pressureAll of these forces combined regulate the amount of fuel that enters the carburetor fuel chamber