2010 Yamaha Motorsports RS Viking Professional Owners Manual - Page 52

Periodic maintenance and adjustment 5. Install the air filter case cover and attach the air filter case by hooking all the fasteners. Close the shroud. 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 6. ESU11910 Carburetors 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. ESU11941 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. ESU11976 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. Your snowmobile can be adjusted to overcome most of the problems found in high-altitude 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 proper carburetion. 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 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. ECS00482 NOTICE G G G Do not run the engine with too much or not enough oil in the oil tank. Oil could spray out or the engine could be damaged. Be sure to change the engine oil after the first 800 km (500 mi) of operation, and every 4000 km (2500 mi) thereafter or at the start of a new season, otherwise the engine will wear quickly. The oil filter cartridge should be replaced after the first 800 km (500 mi) of operation, and every 20000 km (12000 mi) of operation thereafter. 46