2007-2008 Polaris IQ Snowmobiles Service Manual, Page 302Get this manual
Battery and Electrical Systems 2008 IQ Shift RegulatorRectifier
The regulator rectifier on 2008 IQ Shift limits AC Voltage to 14.3 voltsThe module also supplies 12 Vdc to power the exhaust valve solenoidReplace the regulatorrectifier if the AC Voltage is above 14.8 or when there is no 12 Vdc supply on the REDGREEN circuitNOTE: Install the knock sensor fastener clean and dry without applying thread locker or oils
VARIABLE EXHAUST SYSTEM (VES)
Overview
The Polaris VES system uses exhaust valves (1 per cylinder) to control the exhaust port heightThe valves are actuated by controlling cylinder pressure with solenoid, bellows, and series of hosesAt idle speed and up to pre-determined level, the solenoid is powered by the ECU or CDIThis action opens the solenoid's internal valve and allows the cylinder pressure to vent into the atmosphereDuring this time the valves are downTo raise the valves, the ECU or CDI will cut power to the solenoid which will close the vent path to atmosphereThe cylinder pressure will then act upon each valve bellows which will raise each valveOn CFI engines the timing at which the solenoid is turned off is determined by engine RPM, TPS position, and pipe temperatureOn carbureted engines, the CDI will turn the solenoid off at 6700 RPM when the throttle flipper is at least 34 throttle or at 7200 RPM when the throttle flipper is at least 12 throttleNOTE: Solenoid PoweredVent Path Open Solenoid OffVent Path Closed