Honda GL1800 owner's manual: Coolant

Coolant

Your motorcycle’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, overheating, and corrosion.

Coolant Recommendation

Use Pro Honda HP coolant or an equivalent high quality ethylene glycol antifreeze containing corrosion protection inhibitors specifically recommended for use in aluminum engines. Check the antifreeze container label.

Use only distilled water as a part of the coolant solution. Water that is high in mineral content or salt may be harmful to the aluminum engine.

NOTICE

Using coolant with silicate inhibitors may cause premature wear of water pump seals or blockage of radiator passages. Using tap water may cause engine damage.

The factory provides a 50/50 solution of antifreeze and water in this motorcycle. This coolant solution is recommended for most operating temperatures and provides good corrosion protection.

Decreasing the concentration of antifreeze to less than 40% will not provide proper corrosion protection.

Increasing the concentration of antifreeze is not recommended because it decreases cooling system performance. Higher concentrations of antifreeze (up to 60%) should only be used to provide additional protection against freezing. Check the cooling system frequently during freezing weather.

Servicing Your Honda 133

Coolant

Checking & Adding Coolant

Refer to Safety Precautions on page 106.

LEFT SIDE

1. Remove the left engine side cover (page 120 ).
2. With the engine at normal operating temperature, remove the reserve tank dipstick and check the coolant level. If the reserve tank is empty, or if coolant loss is excessive, check for leaks and see your Honda dealer for repair.
3. Add coolant to the reserve tank as required to bring the coolant level to the UPPER level mark. Always add coolant to the reserve tank. Do not attempt to add coolant by removing the radiator cap.
4. Reinstall the left engine side cover.

134 Servicing Your Honda

Coolant

Coolant Replacement

Refer to Safety Precautions on page 106.

Coolant should be replaced by your Honda dealer, unless you have the proper tools and service data and are mechanically qualified. Refer to the official Honda Service Manual (page 218 ).

WARNING Removing the radiator cap while the engine is hot can cause the coolant to spray out, seriously scalding you.

Always let the engine and radiator cool down before removing the radiator cap.

To properly dispose of drained coolant, refer to You & the Environment, page 173 .

NOTICE Improper disposal of drained fluids is harmful to the environment.

Servicing Your Honda 135

Crankcase Breather

Refer to Safety Precautions on page 106.

Service the crankcase breather more frequently if your motorcycle is ridden in the rain or often at full throttle. Service the breather if you can see deposits in the transparent section of the drain tube.

Draining

LEFT SIDE

crankcase breather tube plug

1. Place a drain pan under the crankcase breather tube plug.
2. Remove the left cylinder head side cover (page121).
3. Remove the plug to drain the deposits in the tube.
4. Reinstall the crankcase breather tube plug.
5. Reinstall the left cylinder head side cover.

136 Servicing Your Honda

Final Drive Oil

Oil Recommendation

Checking & Adding Oil

Refer to Safety Precautions on page 106.

RIGHT REAR

1. Place the motorcycle on its center stand on a firm, level surface.
2. Remove the oil filler cap.
3. Check the oil level. It should be flush with the lower edge of the oil filler hole.
4. If the level is low, check for oil leaks. Add the recommended oil through the oil filler hole until it reaches the lower edge of the opening.
5. Install the oil filler cap.

Final Drive Oil

Changing Oil

Refer to Safety Precautions on page 106.

RIGHT REAR

Change the oil with the final drive at normal operating temperature to assure complete and rapid draining.

1. Place the motorcycle on its center stand on a firm, level surface.
2. Place a drain pan under the drain bolt.
3. Remove the oil filler cap and the drain bolt.
4. After the oil has completely drained, check that the sealing washer is in good condition. Reinstall the drain bolt with its sealing washer (or a new washer, if necessary) and tighten it to the specified torque: 14 lbf·ft (20 N·m , 2.0 kgf·m)
5. Fill the final drive with the recommended oil: 4.1 US oz (120 cm³) Make sure the final drive oil level is at the lower edge of the oil filler inspection hole.
6. Install the oil filler cap.

138 Servicing Your Honda

Clutch System

Your motorcycle has a hydraulically-actuated clutch. There are no adjustments to perform, but the clutch system must be inspected periodically for fluid level and leakage.

If control lever freeplay becomes excessive and the motorcycle creeps or stalls when shifted into gear, or if the clutch slips, causing acceleration to lag behind engine speed, there is probably air in the clutch system. See your Honda dealer to have the air bled out of the system.

Clutch Lever Adjustment

Refer to Safety Precautions on page 106.

The distance between the tip of the clutch lever and the grip may be adjusted.

LEFT HANDLEBAR

1. Turn the adjuster dial while pushing the clutch lever forward.
2. Align the index mark on the clutch lever with the numbers on the adjuster dial.
3. Start the engine, pull the clutch lever in, and shift into gear. Make sure the engine does not stall and the motorcycle does not creep. Gradually release the clutch lever and open the throttle. Your motorcycle should move smoothly and accelerate gradually.

Clutch System

Fluid Level Inspection

Refer to Safety Precautions on page 106.

LEFT HANDLEBAR

Check that the fluid level is above the LOWER level mark. If the fluid level is below the LOWER level mark, it indicates fluid leakage. See your Honda dealer for repair.

Other Inspections

• Make sure there are no fluid leaks.

• Check for deterioration or cracks in the hose and fittings.

• Check that the clutch lever assembly is positioned properly and the securing bolts are tight.

140 Servicing Your Honda

Spark Plugs

Spark Plug Recommendation

Use only the recommended type of spark plugs in the recommended heat range.

NOTICE

Using spark plugs with an improper heat range can cause engine damage.

Spark Plug Replacement & Inspection

Refer to Safety Precautions on page 106.

1. Remove the left and right cylinder head side cover (page121).
2. Clean any dirt from around the spark plug bases.
3. Disconnect the spark plug caps. Take care to avoid damaging the spark plug wire when disconnecting the caps.
4. Using the spark plug wrench provided in the tool kit, remove the spark plugs.

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Spark Plugs

5. Inspect the electrodes and center porcelain for deposits, corrosion, or carbon fouling. If the corrosion or deposits are heavy, replace the plug. Clean a carbon or wet-fouled plug with a plug cleaner, if available, or a wire brush.
6. Check the spark plug gap using a wire-type feeler gauge. If adjustment is necessary, bend the side electrode carefully. The gap should be: 0.039 – 0.043 in (1.00 – 1.10 mm)
7. With the plug washers attached, thread the spark plugs in by hand to prevent cross-threading.
8. Tighten each spark plugs:

• If the old plug is good: 1/8 turn after it seats.
• If installing a new plug, tighten it twice to prevent loosening: a) First, tighten the plug: NGK: 3/4 turn after it seats. DENSO: 1/2 turn after it seats. b) Then loosen the plug. c) Next, tighten the plug again: 1/8 turn after it seats.

NOTICE Improperly tightened spark plugs can damage the engine. If a plug is too loose, a piston may be damaged. If a plug is too tight, the threads may be damaged.

9. Reinstall the spark plug caps. Take care to avoid pinching any cables or wires.

side electrode spark plug gap

142 Servicing Your Honda

Suspension

Your front and rear suspension systems use springs and hydraulic damping devices that suspend your weight and most of the weight of your motorcycle.

The spring pre-load for your rear suspension system adjusts the amount of force required to begin compression of the spring.

The oil damper systems hydraulically control the natural compression and rebound of the suspension springs so that traction and comfort are maintained as the wheels ride over road surfaces.

Consider adjusting your rear suspension pre-load whenever you change your normal load, by adding or subtracting a passenger, cargo, or accessories, or when the road or riding conditions change.

The way you ride your motorcycle and the type of ride you want to experience can also influence your suspension needs.

Lower spring pre-load provides a softer ride and is usually preferred for light loads and smooth roads. Higher spring pre-load provides a firmer ride and is recommended for heavy loads, rough road conditions, and faster, more challenging riding.

Rear Suspension Adjustment

The rear suspension can be adjusted for rider (and passenger) weight and riding conditions by changing the spring pre-load.

Do not attempt to disassemble, service, or dispose of the damper; see your Honda dealer. The instructions found in this owner’s manual are limited to adjustments of the shock assembly only.

Suspension

Rear Suspension Spring Pre-load

Rear spring pre-load can be easily increased or decreased using the rear spring pre-load switch on the left front fairing. Then you can comfirm the pre-load position with the multi-display.

This electric rear spring pre-load adjustment system functions only when the ignition switch is ON or ACC, your motorcycle is stopped, and the transmission is in neutral. (When the reverse indicator is ON, the system will not function.)

The spring pre-load system has 26 positions (from 0 to 25) for different road or riding conditions. (Standard position is 0.)

Adjustment

1. Place the motorcycle on its center stand on a firm, level surface. To prevent discharging the battery, make sure the audio system and other electrical accessories are off.
2. Turn the ignition switch to ON or ACC.
3. Push the DOWN or UP side of rear spring pre-load adjustment switch until the desired pre-load is reached.

To increase (HIGH)

To decrease (LOW)

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Suspension

Storing Pre-load Into the Memory You may store two selected adjustments in “MEMO 1” or “MEMO 2”.

1. Adjust the pre-load to the desired position.
2. Push and hold the MEMO 1 or MEMO 2 button until “STORE MEMO 1” or “STORE MEMO 2” blinks in the multi-display. When the blinking stops, the current position is stored in memory.

Selecting the Memorized Position

• Push the MEMO (1 or 2) button to select the memorized position. “CALL MEMO 1” or “CALL MEMO 2” will blink. When the position is selected, “MEMO 1” or “MEMO 2” will turn on.

Pushing the rear spring pre-load switch or the MEMO (1 or 2) button while selecting a memorized position will cancel the calling procedure.

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Suspension

Each MEMO button stores only one pre-load position. Storing a new position erases the previous setting stored in that button’s memory. If you want to add a new position while retaining the current one, use the other memory button.

All stored pre-load positions will be lost if your motorcycle’s battery goes dead or is disconnected.

When “SUS ADJ ERROR” blinks on the display, contact your Honda dealer.

146 Servicing Your Honda

Brakes

The hydraulic braking systems on your motorcycle dissipate the heat generated by the friction of the brake pads on the brake discs as the wheels are slowed.

As the brake pads wear, the brake fluid level will drop. A leak in the system will also cause the level to drop.

Frequently inspect the system to ensure there are no fluid leaks. Periodically inspect the brake fluid level and the brake pads for wear.

If the brake lever or brake pedal freeplay does not feel within the normal range while riding, check the brake pads for wear (page 150 ). Worn pads should be replaced. If the pads are not worn beyond the recommended limit, there is probably air in the brake system. See your Honda dealer to have the air bled from the system.

Front Brake Lever Adjustment

Refer to Safety Precautions on page 106.

The distance between the tip of the brake lever and the grip may be adjusted.

RIGHT HANDLEBAR

1. Turn the adjuster dial while pushing the brake lever forward.
2. Align the index mark on the brake lever with the numbers on the adjuster dial.
3. Apply the brake, release it, then spin the wheel and check that it rotates freely. Repeat this procedure several times.

Brakes

Brake Fluid Recommendation

The recommended brake fluid is Honda DOT 4 Brake Fluid, or any brake fluid of 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.

Fluid Level Inspection

Refer to Safety Precautions on page 106.

If your inspection indicates a low fluid level, have your Honda dealer add the recommended brake fluid.

Do not add or replace brake fluid, except in an emergency. If you do add fluid, have your Honda dealer check the system as soon as possible.

NOTICE

Brake fluid can damage plastic and painted surfaces. Handle with care.

Wipe up spills immediately. Avoid contact with skin or eyes. In case of contact, wash thoroughly and call a doctor immediately if it contacts your eyes.

148 Servicing Your Honda

Brakes

1. Place your motorcycle in an upright position on a firm, level surface.
2. Check the fluid level. Front: It should be above the LOWER level mark. Rear: It should be between the UPPER and LOWER level marks.

If the level is at or below the LOWER level mark, check the brake pads for wear.

Worn pads should be replaced. If the pads are not worn beyond the recommended limit, have your brake system inspected for leaks.

Other Inspections

• Make sure there are no fluid leaks.
• Check for deterioration or cracks in the hoses and fittings.

Servicing Your Honda 149

Brakes

Brake Pad Wear

Refer to Safety Precautions on page 106.

Brake pad wear depends upon the severity of usage, the type of riding, and road conditions. Generally, the pads will wear faster on wet and dirty roads. Inspect the pads at each regular maintenance interval (page 111).

Front Brake LEFT FRONT (right side similar)

Always inspect both pads in both the right and left front brake calipers.

Check the grooves in each pad. If either pad is worn to the bottom of the grooves, replace both pads as a set. See your Honda dealer for this service.

Rear Brake RIGHT REAR

Check the cutouts in each pad. If either pad is worn to the cutout, replace both pads as a set. See your Honda dealer for this service.

150 Servicing Your Honda

Brakes

Brake System Inspection

Refer to Safety Precautions on page 106.

1. Place the motorcycle on its center stand, stop the engine, and place the transmission in neutral.
2. Move the left caliper assembly upward while slowly rotating the rear wheel. The brake system is normal if the rear wheel stops. If the rear wheel does not stop, see your Honda dealer.

LEFT FRONT

brake caliper

LEFT REAR

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