Yamaha YFM40FBZ, YFM40FBHZ Big Bear 400 2010 Owner's Manual
![Yamaha YFM40FBZ, YFM40FBHZ Big Bear 400 2010 manual cover](/images/320c23c1874060faeb36fcb4/thumbs/thumb175x175.webp)
Regular maintenance includes checking the oil level, inspecting and cleaning the air filter, checking tire pressure, and examining brake pads. Refer to the owner's manual for detailed maintenance schedules and procedures.
It is recommended to use Yamalube 4-Stroke oil or any high-quality 4-stroke engine oil with a viscosity of 10W-40. Ensure the oil meets or exceeds the specifications set in the owner's manual.
If your ATV won't start, check the battery charge, ensure the fuel valve is on, verify that the kill switch is in the run position, and inspect the spark plug for wear or damage.
If your ATV stalls, check the air filter for blockages, ensure the fuel is fresh, and inspect the fuel lines for leaks or clogs. Clean the carburetor if necessary.
Locate the idle adjustment screw on the carburetor. Turn it clockwise to increase the idle speed or counterclockwise to decrease it, ensuring the engine runs smoothly at idle.
To clean the carburetor, remove it from the engine, disassemble it carefully, clean all parts with carburetor cleaner, ensure all passages are clear, and reassemble it before reinstalling.
To check the spark plug, remove it using a spark plug socket, inspect for wear or deposits, and replace it if necessary. Use a new plug with the correct gap as specified in the owner's manual.
The recommended tire pressure is typically 4 psi (27.6 kPa) for the front tires and 4 psi (27.6 kPa) for the rear tires. Always refer to the manual for the exact specifications.
Regularly inspect the brake pads for wear, ensure brake fluid is at the correct level, and check for any leaks in the brake lines. Replace brake pads if they are worn beyond the minimum thickness.
To improve battery life, keep the terminals clean and tight, avoid deep discharges, and use a trickle charger if the ATV is idle for extended periods. Regularly check the electrolyte level if applicable.