Electronic servo-controlled power valves are great for providing a wider power output, reduced noise and emissions, along with an improvement in fuel economy. They are not, however, totally service-free. The cables used to connect the servo motor to the valve will, as will most cables, stretch over time and use. Many times the cable for one cylinder will stretch more than the other. Bottom line, when the cables stretch the valve will not fully open and the exhaust port will not be as tall; translation, youâ€™re losing top end horsepower. It may pull good off the line but is really flat at wide open, especially with a good clutching set-up that really loads the engine.
Arctic Cat engines fitted with APV power valves should have their cables checked at least every 1000 miles and adjusted as needed. The cable lengths should be as follows: 2003 Firecat 700: 37.15mm (1.462â€); 2004 Firecat 700: 34.5mm (1.35â€); 2003 ZR/MC 800 & 900: 30.6mm (1.20â€); 2004 ZR/MC 800 & 900: 38.5mm (1.51â€).