Yamaha YFM40FBA, YFM40FBHA Big Bear 400 2011 Owner's Manual
![Yamaha YFM40FBA, YFM40FBHA Big Bear 400 2011 manual cover](/images/5be1ca54dde044072050bdb9/thumbs/thumb175x175.webp)
For optimal performance, use 10W-40 or 20W-50 four-stroke motorcycle oil. Ensure the oil meets JASO MA standards for wet clutch compatibility.
Clean the air filter every 20 hours of operation or more frequently if riding in dusty conditions. Replace the air filter if it shows signs of wear or damage.
The recommended tire pressure is 4.4 psi (30 kPa) for the front tires and 3.6 psi (25 kPa) for the rear tires. Always check tire pressure when the tires are cold.
First, check the battery charge and connections. Ensure the fuel is fresh and the fuel valve is open. Inspect the spark plug for wear or fouling and replace if necessary.
After 100 hours, change the engine oil, check and adjust the valve clearance, inspect the drive belt, and lubricate all grease points.
Locate the idle speed adjustment screw on the carburetor. Turn the screw clockwise to increase idle speed or counterclockwise to decrease it. The idle speed should be set to 1,450-1,550 RPM.
Clean the ATV thoroughly, change the oil, stabilize the fuel, disconnect the battery, and store it in a dry, covered area. Inflate the tires to the recommended pressure and cover the ATV to protect it from dust and moisture.
Ensure the ATV is on a level surface and the engine is cool. Remove the radiator cap and check if the coolant is at the top of the filler neck. Add coolant if necessary, and make sure the coolant reservoir is between the "Full" and "Low" marks.
Stop the ATV immediately and turn off the engine. Allow it to cool down before checking the coolant level. Inspect the radiator and cooling fan for obstructions and ensure the coolant is at the correct level.
Regular maintenance such as keeping the air filter clean, maintaining proper tire pressure, and ensuring the carburetor is tuned can help improve fuel efficiency. Avoid aggressive acceleration and maintain a steady speed when riding.