2010 Yamaha Motorsports Big Bear 400 4x4 IRS Owners Manual - Page 106

EWB02340 ECB00480 WARNING Do not start the engine when cleaning the spark arrester, otherwise it could cause injury to the eyes, burns, carbon monoxide poisoning, possibly leading to death, and start a fire. Always let the exhaust system cool prior to touching exhaust components. EBU23940 NOTICE The carburetor has been set and extensively tested at the Yamaha factory. Changing these settings without sufficient technical knowledge may result in poor performance of or damage to the engine. EBU24000 Adjusting the engine idling speed The engine idling speed must be checked and, if necessary, adjusted as follows at the intervals specified in the periodic maintenance and lubrication chart. TIP A diagnostic tachometer is needed to make this adjustment. 1. Start the engine and warm it up. TIP The engine is warm when it quickly responds to the throttle. 2. Attach the tachometer to the spark plug lead. Adjusting the carburetor The carburetor should be checked and, if necessary, adjusted at the intervals specified in the periodic maintenance and lubrication chart. The carburetor is an important part of the engine and requires very sophisticated adjustment. Therefore, most carburetor adjustments should be left to a Yamaha dealer, who has the necessary professional knowledge and experience. The adjustment described in the following section, however, may be performed by the owner as part of routine maintenance. 8 8-25