Polaris exhaust valves open with cylinder pressure. As you go up in elevation, cylinder pressures are reduced causing exhaust valves to open later than they should or in some cases not at all. This can cause poor and inconsistent top-end horsepower. Changing to lighter exhaust valve springs allows exhaust valves to open at the proper time, maintaining proper top-end horsepower and running consistency. Sold per each.
STA14-117 recommended on 2008-10 Polaris 800 CFI models at elevation above 5000’
