Yamaha YFM350FW Big Bear 4x4 service schedule

1. Park on level ground. Warm the engine for several minutes, then stop it and take the key out. Hot oil burns: wear gloves.
2. Put a container under the engine and remove the dipstick and the drain plug.
3. Take care: when the drain plug comes out, the compression spring, oil strainer and O-ring fall out with it. Do not lose them.
4. Remove the oil filter cover (three bolts) and the filter element.
5. Clean the oil strainer and the filter in solvent (fit a new filter at every change). Inspect the O-rings and replace any that are damaged.
6. Refit the filter, O-ring, filter cover, strainer and spring with the drain plug. Do not forget the O-ring, spring and strainer. Tighten the drain plug to 32 N·m and the filter cover bolts to 8 N·m.
7. Fill with 3.0 L of the recommended oil and refit the dipstick.
8. Warm the engine at idle for a few minutes and check for leaks. If oil leaks, stop the engine at once and find the cause.
9. Check the oil pressure as the manual describes: slightly loosen the oil gallery bolt on the cylinder head with a cloth around it. Oil should seep out within one minute of starting; if not, stop the engine at once so it does not seize. Retighten the bolt to 7 N·m.
10. Wait a few minutes, check the level is between the dipstick marks (dipstick resting in, not screwed in), and dispose of the old oil properly.

Tools: Drain tray (5 L), Socket set, Torque wrench (8–32 N·m), Solvent and brush, Funnel, Gloves

1. Let the engine cool and take the key out.
2. Remove the plug cap and the plug.
3. Look at the plug. A very white centre electrode insulator can mean an air leak or carburettor problem: have a dealer look rather than guessing. Replace the plug if the electrodes are badly eroded.
4. Set the gap to 0.6–0.7 mm.
5. Clean the gasket surface, fit a new gasket, wipe the threads and tighten to 17.5 N·m.

Tools: Plug spanner, Feeler gauge, Torque wrench (17.5 N·m)

1. Only check with the engine cold.
2. The clearance figure and procedure are in the Yamaha service manual, not the owner's manual. If you do not have them, have your dealer do it.
3. A tapping engine or loss of power can mean the clearance is out.

Tools: Feeler gauges, Service manual

1. Warm the engine for a few minutes at about 1,000–2,000 rpm, outdoors. Exhaust fumes are poisonous.
2. Connect a tachometer and set the idle to 1,450–1,550 rpm with the throttle stop screw: in to raise, out to lower.
3. Check the throttle lever free play is 3–5 mm with the engine idling; adjust at the lever and tighten the locknut.
4. Check the fuel hose for cracks or damage and replace if needed. Petrol is highly flammable.
5. Do not alter other carburettor settings: Yamaha says they were set at the factory and disturbing them causes poor running.

Tools: Diagnostic tachometer, Screwdriver

1. Park on level ground, engine off, key out.
2. Front fluid: turn the handlebars so the reservoir top is level and check the fluid is above the LOWER mark. Refill only with the same type. Keep water out. Wipe up spills at once: brake fluid damages paint and plastic. If the level keeps falling, have a dealer check it.
3. Front shoes: turn the wheel so the rubber plug on the hub is at the top or bottom, remove it and check the lining. Standard 4 mm, wear limit 1 mm. If worn past the limit, have a dealer replace the shoes as a set.
4. Front lever free play at the adjusting bolt should be 2–5 mm. If the lever travels more than 30 mm before braking when applied, have a dealer adjust the brake or replace the shoes.
5. Rear brake: fully apply it and check the wear indicator. If it reaches the wear limit line, have the shoes replaced as a set.
6. Rear adjustment: brake pedal free play 20–30 mm at the brake rod nut; rear brake lever 0–1 mm gap at the cable adjusting nut, then 4–8 mm free play at the lever pivot. Tighten the locknuts.
7. Afterwards make sure the brakes work smoothly, do not drag and are not spongy. Have air bled out by a dealer if they feel spongy.

Tools: Rule, Screwdriver, Spanners, Torch

1. With the engine off, loosen the clutch adjuster locknut.
2. Slowly turn the adjusting bolt anticlockwise until resistance is felt, then turn it 1/8 turn clockwise.
3. Tighten the locknut to 15 N·m.
4. If unsure, have your dealer do it.

Tools: Spanner, Screwdriver, Torque wrench (15 N·m)

1. Check cables for fraying, kinks or damaged outer covering. Corroded or damaged cables can stick and cause an accident; have them replaced.
2. Lubricate the inner cables and cable ends.
3. Lubricate the pivots of the brake levers, brake pedal and shift pedal.
4. Check each control works smoothly afterwards.

Tools: Cable luber or oil can, Rag

1. Park on level ground, engine off, key out, parking brake on.
2. Final gear: remove the final gear case cover. Put a container under it, remove the filler bolt and drain plug and let it drain.
3. Refit the drain plug at 23 N·m. Fill with 0.19 L of SAE 80 GL-4 hypoid oil, up to the brim of the filler hole. Refit the filler bolt at 23 N·m and the cover.
4. Differential: remove the differential gear case cover, put a container under it, remove the filler bolt and drain plug and let it drain.
5. Refit the drain plug at 12 N·m. Fill with 0.18 L of GL-5 hypoid oil for limited-slip differentials. Refit the filler bolt at 12 N·m.
6. Do not let any dirt into the gear cases. Check for leaks and refit the covers.

Tools: Small drain tray, Socket set, Torque wrench (12–23 N·m), Oil syringe or squeeze bottle

1. Park on level ground, engine off, key out.
2. Check the protective boots on both front axles for holes or tears, turning the steering to see all round them.
3. Have any damaged boot replaced by your dealer.

Tools: Torch, Rag

1. If dust or water has collected in the check hose at the bottom of the air filter case, empty the hose and clean the element and case.
2. Remove the seat and the air filter case cover. Remove the element and separate it from its guide.
3. Wash it gently but thoroughly in parts cleaning solvent. Never use petrol or low-flash-point solvents: they can catch fire or explode.
4. Squeeze out the excess solvent and let it dry. Do not twist the element.
5. Inspect it and replace it if damaged.
6. Apply foam air filter oil. The element should be wet but not dripping.
7. Refit the element on its guide and refit the assembly and cover. Never run the engine without the element.

Tools: Parts cleaning solvent (not petrol), Gloves, Screwdriver