This Maintenance Schedule below is to show you some basic and important things you should do to your ATV. Some things written may not need to be applied to your specific ATV. Most of the information is for the Honda Rancher 420cc.
ATV Tip’s Maintenance Schedule
Whichever Comes First
Air Cleaner
Air Cleaner Housing Draining Tube
Spark Plug
Engine Oil
Engine Oil Filter
Radiator Coolant
Brake Fluid
Brake Shoes Wear
Brake Pads Wear
Spark Arrester
I: inspect and clean, adjust, lubricate, or replace, if necessary
C: clean
A: adjust
L: lubricate
R: replace
This table was created by ATV Tips, based on the information given in the Owner’s Manual of the Honda 2009 TRX420TM (Honda Rancher 420cc) on Page 92 and 93.


Air Cleaner
Proper air cleaner maintenance is very important for off-road vehicles. A dirty, water-soaked, worn-out, or defective air cleaner will allow dirt, dust, mud, and other impurities to pass into the engine. Service the air cleaner more frequently if you ride in unusually wet or dusty areas. Your ATV’s air cleaner has very specific performance requirements. Use a new Honda Genuine air cleaner specified for your model or an air cleaner of equal quality. Proper air cleaner maintenance can prevent premature engine wear or damage, expensive repairs, low engine power, poor gas mileage, and spark plug fouling.
  1. Remove the seat.
  2. Unlatch the retainer clips.
  3. Remove the air cleaner housing cover.
  4. Loosen the screw and remove the air cleaner assembly from the air cleaner housing.
  5. Unscrew the clamp.
  6. Remove the air cleaner from the air cleaner body.
  7. Gently wash the air cleaner in clean, non-flammable (high flash point) solvent such as Kerosene – not gasoline. After cleaning, gently squeeze out the remaining solvent. Avoid twisting or wringing the air cleaner will not fully absorb the oil.
  8. Inspect for tears or cracks in the foam or seams of the air cleaner. Replace the air cleaner if it is damaged.
  9. Allow the air cleaner to dry thoroughly before applying oil. A wet air cleaner will not fully absorb the oil.
  10. Pour clean Pro Honda Foam Filter Oil or an equivalent over the entire surface of the air cleaner. Use both hands to evenly spread the oil into the air cleaner. Gently squeeze out any excess oil.
  11. Install the air cleaner on the air cleaner body.
  12. Apply a thin coat of grease to the sealing surface of the air cleaner assembly.
  13. Install the clamp.
  14. Insert the air cleaner assembly into the air cleaner housing.
  15. Fasten the screw.
  16. Reassemble by reversing the disassembly sequence.


Air Cleaner Housing Drain Tube
The air cleaner housing drain tube should be serviced in accordance with the Maintenance schedule. (riding through water may require more frequent inspection.) If deposits can be seen in the drain tube, the tube must be cleaned before starting the vehicle.
  1. Remove the drain tube by removing the clip under the air cleaner housing.
  2. Drain the deposits.
  3. Reinstall the drain tube, securing it with the clip.


Spark Plug
Use only the recommended type of spark plug in the recommended heat range for your specific model.
Inspection and Replacement
  1. Remove the seat and left side cover.
  2. Remove the left tank side cover by removing the bolts.
  3. Clean any dirt from around the spark plug base.
  4. Disconnect the spark plug cap. Take care to avoid damaging the spark plug wire when disconnecting the cap.
  5. Using a spark plug wrench provided in the tool kit, remove the spark plug.
  6. Inspect the electrodes and center porcelain for deposits, corrosion, or carbon fouling. If the corrosion of deposits are heavy, replace the plug. Clean a carbon or wet-fouled plug with a plug cleaner, if available, or a wire brush. Inspect the spark plug electrodes for wear. The center electrode should have a flat tip and sharp edges, and the side electrode should not be eroded. If the electrodes and insulator tip appear unusually fouled or burned, we suggest that you contact your Honda dealer.
  7. Discard the spark plug if there is apparent wear or if the insulator is cracked or chipped.
  8. Using a wire-type feeler gauge, check the spark plug gap. If adjustment is necessary, bend the the side electrode carefully.
  9. With the plug washer, thread the spark plug in by hand to prevent cross-threading.
  10. Tighten the spark plug.
  11. Connect the spark plug. Take care to avoid pinching any cables or wires.
  12. Install the remaining parts in the reverse order of removal.

Engine Oil
Engine oil quality is a major factor that affects both the performance and the service life of the engine. Using the proper oil and filter, and regularly checking, adding, and changing oil will help extend your engine’s life. Even the best oil wears out. Changing oil helps get rid of dirt and deposits in the engine. Operating the engine with old or dirty oil can damage your engine. Running the engine with insufficient oil can cause serious damage to the engine and transmission. When running in very dusty conditions, oil changes should be performed more frequently than specified in the maintenance schedule.
Recommend Oil
API classification
SG or higher except oils labeled as energy conserving on the circular API service label
Viscosity (weight)
SAE 10W-30
JASO T 903 standard
Suggested oil
Pro Honda GN4 4-stroke oil or an equivalent motorcycle oil.
Checking and Adding Oil
  1. Park your ATV on a firm, level surface.
  2. Start the engine in a well-ventilated area and let it idle for 3-5 minutes. Stop the engine and wait 2-3 minutes.
  3. Remove the seat.
  4. Unsnap and remove the left side cover.
  5. Remove the oil filler cap/dipstick from the front crank case and wipe it clean.
  6. Insert the oil filler cap/dipstick without screwing it in, then remove the oil filler cap/dipstick and check the oil level. The oil level should be between the upper level mark and the lower level mark on the oil filter cap/dipstick.
  7. If required, add the specified oil into the filler cap hole, up to the upper level mark on the oil filler cap/dipstick. Do not overfill.
  8. Reinstall the oil filler cap/dipstick.
  9. Install the left side cover.
  10. Install the seat.


Engine Oil Filter
This procedure requires mechanical skill and professional tools such as a torque wrench and oil filter wrench, as well as a means for disposing of the drained fluid.
Drain the Engine Oil
  1. With the ATV on the level ground, remove the seat, left side cover and the oil filler cap/dipstick from the front crank case.
  2. Place an oil drain pan under the crank case and remove the engine oil drain plug and sealing washer.
Install a new Engine Oil Filter
  1. Remove the seat.
  2. Unsnap and remove the right side cover.
  3. Remove the oil filter cover by removing the bolts. Let the remaining oil drain out. Discard the oil filter in an approved manner.
  4. Check that the oil filter cover o-rings are in good condition and then install a new oil filter. Use only the Honda genuine oil filter or a filter of equivalent quality specified for your model. Using the wrong Honda filter or a non-Honda filter which is not of equivalent quality may cause engine damage.
  5. Reposition the spring to the engine crank case and install a new oil filter with the rubber seal facing out, away from the engine. You will see the “Outside (Towards Filter Cover)” mark on the filter body near the seal.
  6. Reinstall the oil filter cover, making sure the bolts are tightened to the specified torque.
  7. Pour the drained oil into a suitable container and dispose of it in an approved manner.
  8. Install the right side cover.
Add Engine Oil
  1. Check that the drain plug sealing washer is in good condition. If necessary, replace the sealing washer.
  2. Reinstall the oil drain plug and tighten it to the specified torque.
  3. Fill the crank case with the recommended grade oil approximately 3 US quarts.
  4. Reinstall the oil filler cap/dipstick.
  5. Start the engine and let it idle for 3-5 minutes.
  6. Stop the engine, wait 2-3 minutes and check the oil level. Make sure the oil is between the upper and lower lever marks on the oil filler cap/dipstick. If necessary, add more oil but do not overfill.
  7. Check that there are no oil leaks.
  8. Install the left side cover.
  9. Install the seat.
Radiator Coolant
Your ATV’s liquid cooling system dissipates engine heat through the coolant jacket that surrounds the cylinder and cylinder head. Maintaining the coolant will allow the cooling system to work properly and prevent freezing, over heating, and corrosion.
Checking and adding Coolant
  1. Make sure the vehicle is on level ground.
  2. With the engine at normal operating engine temperature, check the coolant level in the reserve tank. It should be between the UPPER and LOWER level marks. If the reserve tank is empty, or if coolant loss is excessive, check for leaks and see your Honda dealer for repair.
  3. Remove the seat.
  4. Unhook the rubber strap.
  5. Remove the rear fender cover and reserve tank cap. Always add coolant to the reserve tank. Do not attempt to add coolant by removing the radiator cap.
  6. Add coolant to the reserve tank as required to bring the coolant level to the UPPER level mark.
  7. After adding coolant, install the reserve tank cap and rear fender cover.
  8. Fasten the rubber strap.
  9. Install the seat.


Brake Fluid
The hydraulic disc brakes (front) and single mechanical drum brake (rear) on your ATV dissipate heat generated by the friction of the brake pads on the disc (front) and the brake shoes on the drums (rear) as the wheels are slowed.
Hydraulic disc Front Brake
As the front brake pads wear, brake fluid will drop. A leak in the system will also cause the level to drop. There are no adjustments to perform, but fluid level and pad wear must be inspected periodically. The system must be inspected frequently to ensure there are no fluid leaks. If the right brake lever freeplay does not feel within the normal range while riding, check the brake pads for wear. Warn pads should be replaced. If the pads are not warn beyond the recommended limit, there is probably air in the brake system. (See your service dealer to have the air bled from the system)
Mechanical Drum Rear Brake
If the rear brake lever/parking brake lever or brake pedal freeplay does not feel within the normal range while riding, check the brake shoes for wear.
Recommended Brake Fluid
The recommended brake fluid is Honda DOT 4 brake fluid, or any brake fluid with equal quality and performance. Use fresh brake fluid from a sealed container. Be sure to read the label before opening the sealed container. An opened container may be contaminated or may have absorbed moisture from the air.
Brake Shoe Wear
The rear brake is equipped with an external brake wear indicator that lets you check brake wear without disassembly. Application of the brake control causes the arrow on the brake arm to move toward a reference mark on the brake panel.
  1. Apply the brake control and check the movement of the arrow on the brake arm.
  2. Replace the brake shoe if the arrow aligns with the reference mark on the brake panel upon full application of the brake. If replacement is necessary, (see your service dealer).


Brake Pad Wear
Brake pad wear will depend upon the severity of usage and riding conditions. The pads will wear faster in wet or muddy conditions. Inspect the pads visually during all regular service intervals to determine the pad wear.
Check the wear indicator. If the wear indicator aligns with the edge of the reference mark, both pads must be replaced, (see your service dealer for this replacement). Always inspect both pads in both the right and left front brake calipers.


Spark Arrester
The spark arrester must be serviced every 100 operating hours to maintain its efficiency. Regular servicing prevents carbon build up (which can diminish engine performance) and also complies with USDA regulations for regular maintenance to assure proper function. The spark arrester prevents random sparks from the combustion process in your engine from reaching the environment.
The use of safety glasses is recommended for this procedure.
Because of the possible fire hazard, check that there are no combustible materials in the area before purchasing the spark arrester.
  1. Select a well-ventilated area free of combustible materials and make sure the exhaust pipe is cool.
  2. Remove the bolt.
  3. Start the engine and rev it up approximately 20 times while momentarily creating exhaust system back pressure by blocking the end of the muffler with a shop towel.
  4. Stop the engine and allow the exhaust pipe to cool.
  5. Reinstall the bolt securely.
Most of the information above was taken from the Owner’s Manual of the Honda 2009 TRX420TM (Honda Rancher 420cc).