2011 Yamaha Motorsports RS Venture GT Owners Manual - Page 83

Periodic maintenance and adjustment 10. Install the headlight unit bolts and windshield stay bolts, and then tighten them to their specified torques. Tightening torques: Headlight unit bolt: 3.0 Nm (0.30 m·kgf, 2.2 ft·lbf) Windshield stay bolt: 14 Nm (1.4 m·kgf, 10 ft·lbf) 11. Install the top cover and the shroud. ESU11911 Carburetors (RST90) The carburetors are an important part of the engine and its emission control system, which require very sophisticated adjustment. Therefore, carburetor adjustments should be left to a Yamaha dealer, who has the necessary professional knowledge and experience. ESU13980 High-altitude settings Operating at high altitude reduces the performance of a gasoline engine about 3% for every 305 m (1000 ft) of elevation. This is because there is less air as altitude increases. Less air means less oxygen available for combustion. RS90GT / RS90LTGT / RST90GT: Your snowmobile utilizes an electronic fuel injection system that delivers the optimal air/fuel ratio required by the engine. Therefore, the fuel injection system does not need to be adjusted, even for operation at high altitude. RST90: Your snowmobile can be adjusted to overcome most of the problems found in highaltitude riding. Carburetor adjustments are the most important. Less air at high altitude makes the air/fuel ratio too rich, which can cause poor performance. Common problems are hard starting, bogging, and plug fouling. Proper carburetion adjustments will correct the air/fuel ratio. Be sure to have a Yamaha dealer make these adjustments. Remember: Less air at higher altitude means there is less horsepower available, even with the optimal air/fuel ratio. Expect acceleration and top speed to be reduced at higher altitudes. To overcome operating with less power at high altitudes, your snowmobile may also require different settings for the drive chain gears and V-belt clutch to avoid poor performance and rapid wear. If you plan to operate your snowmobile at an altitude different from the area where you bought it, be sure to consult a Yamaha dealer. The dealer can tell you if there are any changes necessary for the altitude where you plan to ride. NOTICE: The drive chain gears and V-belt clutch should be adjusted when operating above a high altitude of 900 m (3000 ft). Consult a Yamaha dealer. [ECS00431] ESU11950 Valve clearance The valve clearance changes with use, resulting in improper air-fuel mixture and/or engine noise. To prevent this from occurring, the valve clearance must be adjusted by a Yamaha dealer at the intervals specified in the periodic maintenance chart. ESU13793 Engine oil and oil filter cartridge The engine oil level should be checked before each use. In addition, the oil must be changed and the oil filter cartridge replaced at the intervals specified in the periodic maintenance and lubrication chart. EWS00370 WARNING Engine oil is extremely hot immediately after the engine is turned off. Coming into contact with or getting any engine oil on your clothes could result in burns. 77