Trailtoy is mostly correct.
Actually the hose FROM the control soleniod is vented to atmosphere... that end is hooked up to nothing and is left dangling in the engine bay behind the engine... it makes a mess.
There is a hose from each exhaust valve to a "Y" fitting, a hose from the "Y" fitting to the exhaust Valve control solenoid and a hose from the solenoid that is left vented to the atmosphere.
Crappy perf?
When were the exhaust valves last cleaned?
Have the exhaust bellows been updated to the new ones?
Check the exhaust valves themselves for cracks or broken shafts.
Have you dissassembled the exhaust valves and CAREFULLY checked the exhaust valve bellows for cracks or splits?
What condition are the throttle body boots that connect the throttle bodies to the reed blocks?
What is the compression in the engine?
Does it idle well? Backfire?
When was the fuel filter changed last?
What quality of gas are you using and can you verifiy that there is no water in your tank? How old is the gas in the sled?
Have you checked your sparkplugs/replaced them and are the caps secure on them?
All of the normal functional check in general.
Have all of the updates been done?
What airbox is on the sled?
What engine mods have been done (pipe, can etc)?
Do you have any MFD blink codes??
MFD Blink Codes
The check engine LED will display a blink code whenever the
ECU determines there is a problem with one or more of the
sensors.
When a blink code is displayed, the CHECK ENGINE light will
illuminate for 1/2 second “on” and 1/2 second “off” with a 1
second “off” interval between close.
DTC Troubleshooting
Always use the Digital Wrench diagnostic software program to
troubleshoot DTCs, MFD blink codes, and overall performance
problems.
VARIABLE EXHAUST SYSTEM (VES)
Overview
The Polaris VES system uses exhaust valves (1 per cylinder) to
control the exhaust port height. The valves are actuated by
controlling cylinder pressure with a solenoid, bellows, and a
series of hoses.
At idle speed and up to a pre-determined level, the solenoid is
powered by the ECU or CDI. This action opens the solenoid’s
internal valve and allows the cylinder pressure to vent into the
atmosphere. During this time the valves are down.
To raise the valves, the ECU or CDI will cut power to the
solenoid which will close the vent path to atmosphere. The
cylinder pressure will then act upon each valve bellows which
will raise each valve.
On CFI engines the timing at which the solenoid is turned off is
determined by engine RPM, TPS position, and pipe
temperature.
NOTE: Solenoid Powered = Vent Path Open
Solenoid Off = Vent Path Closed
900 LIBERTY VES DISASSEMBLY
1. Carefully remove theVES cover bolts (A) cover (B) and spring (C), do not distort the springwhen removing it from the cover.
Spring is under pressure, hold cover tightly against the assembly when removing the cover.
2. Remove the bellows nut (E), bellows (E) and bellows washer (F).
3. Remove the base bolts (K) and remove the base assembly (G) and guillotine (J) from the cylinder.
4. Remove the gasket (H) from the VES base (G) and clean the guillotine (J) with carbon clean or oven cleaner.
900 LIBERTY VES ASSEMBLY1. Place a new gasket (H) on the valve base (G).
2. Place the guillotine (J) in the valve base.
3. Insert the base bolts (K) and torque to 12 ft. lbs. (16 Nm).
4. Place the bellows washer (F) and the bellows (E) on the valve base.
5. Apply Loctite 242 to the bellows nut (D) and torque to 12 ft. lbs. (16 Nm).
6. Install spring (C) and valve cap (B) on to the base and torque the cover bolts (A) to 9 ft.lbs. (12 Nm).
Exhaust Valve Cleaning
The exhaust valve guillotines must be cleaned to ensure
maximum engine performance and throttle response.
1. Remove the vent hose from the EV base fitting.
2. Remove the two fasteners that secure the valve assembly
to the cylinder, but not the two screws that secure the cover
to the EV base.
3. Carefully extract the guillotine out of the cylinder. Discard
the gasket.
4. Using a clean rag or shop towel, remove the oil residue from
the cylinder, guillotine, and EV base.
5. Inspect the guillotine for signs of damage. Replace
guillotine if damage is found, and inspect the cylinder and
piston for damage.
6. Clean the guillotine with brake cleaner and a piece of fine
steel wool. Clean only to remove hardened carbon deposits.
7. Once clean, rinse blade with mild detergent and water. Dry
completely.
8. Install a new gasket, then reinstall the EV assembly. Apply
Loctite 242 to the fastener threads, then torque to
specification.
9. Reconnect the vent hose.
.
