How to Change Coolant in Bikes

by Contributing Writer; Updated June 12, 2017

Motorcycle coolant, though not usually considered a main concern, must be changed on occasion. Coolant has a tendency to become less effective and to become contaminated over time. Replacement coolant is cheap, and so it is wise to replace regularly.

Under The Hood:

 How to Change the Coolant on an Aprilia RS125

Mix one quart of aluminum-safe glycol ethylene antifreeze with one quart of distilled water in a two-quart plastic container.

Select a level work space and mount the motorcycle on a wheel chock to support it in an upright position. Let the engine cool for a minimum of one hour.

Remove the two bolts above the left front turn signal, followed by the three bolts joining the left side fairing to the left lower fairing, using an Allen wrench. Remove the bolt from the left inner fairing panel, near the front wheel, and the bolt behind the left side fairing air duct. Pull the left side fairing away from the motorcycle and unplug the front turn signal connectors from the motorcycle's wiring harness.

Insert the ignition key into the seat release latch, located below the left side of the fuel tank. Turn the key counterclockwise and pull the seat off. Remove the mounting bolt from the front of the fuel tank, near the handlebars, using an Allen wrench. Lift the tank up and away from the frame, then support it in its fully raised position using the prop rod included with the motorcycle's tool kit.

Remove the filler cap from the coolant expansion tank, located between the main frame rails above the engine near the battery. Place a two-quart resealable plastic container below the coolant drain plug, located on the left side of the engine near the front engine mount. Unscrew the drain plug using an Allen wrench. Let the coolant drain to a light trickle, then screw the drain plug into place. Tighten the plug to 17 inch-pounds using a torque wrench.

Fill the coolant expansion tank with your pre-mixed antifreeze until the fluid level is flush the "Full" mark imprinted into the side of the tank.

Place a shop towel around the drain screw on the top left corner of the radiator. Loosen the screw using a Phillips screwdriver. Tighten the screw once antifreeze begins to seep out from the loosened screw. Soak up any antifreeze released from the screw using the shop towel.

Refill the coolant expansion tank, if the fluid level has decreased to the "Fill" mark.

Place a shop towel around the radiator union drain screw, located directly below the left side of the coolant expansion tank. Loosen the screw using a Phillips screwdriver. Tighten the screw once antifreeze begins to seep out from the loosened screw. Soak up any antifreeze released from the screw using the shop towel.

Refill the coolant expansion tank, if the fluid level has decreased to the "Fill" mark.

Lower the fuel tank onto the motorcycle's frame and screw the mounting bolt into place. Tighten the bolt to 5 foot-pounds. Reinstall the seat, then push down on the front of it until the seat latch clicks into place.

Hold the left side fairing panel against the motorcycle. Reach behind the fairing and plug the front turn signal connectors into the motorcycle's wiring harness. Screw the left side fairing panel bolts into place.

Items you will need

  • One quart, aluminum-safe ethylene glycol antifreeze

  • One quart, distilled water

  • Two-quart resealable plastic containers

  • Wheel chock

  • Allen wrench set

  • Ignition key

  • Torque wrench

  • Shop towels

  • Phillips screwdriver

 How to Change the Coolant on a Honda VTX 1800

Pull the motorcycle up on a front wheel chock if you own one. This will give you easier access to the radiator.

Remove any aftermarket radiator cover you may have installed, as most block the radiator drain plug.

Place a bucket underneath the radiator drain bolt and remove it using a 12 mm open-end wrench. Let all the coolant drain out of the radiator. This can take anywhere from 30 seconds to several minutes.

Replace the drain bolt using a 12 mm wrench. Tighten the bolt as you would any lock-nut.

Press down and turn to open the radiator cap on the right side of the motorcycle.

Pour in pre-mixed antifreeze coolant slowly. It is important that you use pre-mixed fluid or mix pure antifreeze with 50 percent water before you pour it into the radiator, as pure antifreeze won't keep the motor as cool. Allow the liquid time to work its way around the piping of the radiator. When you see the coolant rise up close to the top of the reservoir, you can be sure its full.

Replace the radiator cap carefully, making sure to get it on correctly. The side tabs on the cap must match up to the grooves on the housing before the cap can be twisted into place.

Items you will need

  • Front wheel block (optional)

  • Bucket

  • 12 mm open-end wrench

  • Pre-mixed antifreeze coolant

 How to Change the Coolant on a 2001 Yamaha Kodiak 400

Park your ATV on a level surface and let the engine cool down. Locate the coolant reservoir, which is situated in the middle of the ATV, between the oil filter cartridge and V-belt cooling duct check hose, and just below the fuel clock. Pull off the side panel, then unscrew the reservoir cap.

Slide a drain pan underneath the engine. Remove the coolant drain bolt to drain the coolant. Use a trough to protect the footrest from coolant.

Remove the front carrier and the adjoining panel. Detach the hose from the reservoir to begin draining the coolant. Once again, you will have to position a drain pan below.

Flush the system with distilled water. Replace the coolant reservoir hose and drain caps for the radiator and the water pump and refill the tank by pouring a mixture of coolant and distilled water through a funnel until it hits the maximum level mark. Check your owner's manual for the correct ratios.

Reinstall the paneling and replace the coolant tank cap and coolant reservoir cap. Start your engine, and let it idle for a few minutes. Check the coolant level and add more if it is low. Finally, check for leaks.

Items you will need

  • Drain pan

  • Wrench

  • Trough

  • Coolant

  • Distilled water

 How to Change Coolant on a Kawasaki Drifter Motorcycle

Remove the rider's seat. Locate the mounting bolts beneath the seat's flaps and remove them with a hex socket. Lift the rear of the seat upwards and pull it to the rear of the motorcycle to disengage the seat's catch tab from the frame.

Unscrew the fuel tank's lower mounting bolt, located at the base of the tank, using a hex socket. Disconnect the vent hoses from the fuel tank. Place a wooden block over the seat mounting point on the frame. Pull the fuel tank to the rear of the motorcycle and lay it on the wooden block.

Locate the radiator cap on the right side of the motorcycle. Twist the radiator cap counter-clockwise to remove it. Set the radiator cap aside for now.

Locate the drain plug on the bottom of the radiator. Place a large container beneath the drain plug. Using a hex socket, remove the drain plug and allow the coolant to drain. Inspect the drain plug O-ring for damage, replace the O-ring if it is torn. Install the drain plug and tighten it with a hex socket.

Remove the water pump drain plug from the right engine cover with a hex socket. Allow any remaining coolant in the engine to drain into your container. Reinsert the water pump drain plug, tightening it with a hex socket.

Remove the right side engine cover, using an Allen socket to remove the cover's mounting bolts. Pull the engine cover away from the motor to access the coolant reservoir. Remove the reservoir from the motor, using a hex socket to remove the reservoir's mounting bolts. Pull the coolant hose off of the reservoir to drain any remaining coolant.

Clean the reservoir using a bottle brush to remove any buildup. Reattach the coolant hose to the reservoir. Fill the radiator with coolant until it is level with the bottom of the radiator's filler neck. Remove the filler cap from the reservoir and add coolant into the reservoir. Continue to fill until the coolant is level with the "Full" mark imprinted on the reservoir. Replace the reservoir's filler cap.

Check all of the drain plugs to ensure that they are tightened. Start the motor to pull coolant through the radiator and coolant lines. Bubbles should form within the radiator and should be visible from the radiator filler neck. Stop the motor once the bubbling from the radiator coolant dissipates. Reinstall the radiator filler cap. Refill the coolant reservoir to the "Full" mark.

Reinstall the reservoir onto the motor, using a hex socket to tighten the mounting bolts. Mount the right side engine cover, using an Allen socket to tighten all mounting bolts.

Items you will need

  • Socket wrench

  • Hex socket set

  • Allen socket set

  • Wooden block

  • Radiator drain plug O-ring

  • Coolant, 50/50 mix for aluminum motors

 How to Change Coolant in a Motorcycle


Place a bucket or pan under the motorcycle to catch the used coolant.

Remove the coolant drain bolt from the underneath of the motorcycle. Allow the coolant to drain out completely. This shouldn't take long.

Use a clean rag to remove any debris or contaminants from the coolant drain bolt.

Replace the drain bolt.

Open the coolant cap (usually located just under the front fairing of the motorcycle).

Pour in the amount of motorcycle antifreeze suggested in your motorcycle's owner's manual.

Replace the coolant cap. To seal it tightly, make sure the cap is twisted completely.

Items you will need

  • Motorcycle antifreeze Standard tool kit

About the Author

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