Inspect every 6 000 km (4 000 miles, 12 months) and replace every 12 000 km (7 500 miles, 24 months).
No.1 (front) spark plug removal
Remove the cowling. (7-5).
Remove the radiator mounting bolt 1.
Move the radiator lower side to forward.
Remove the spark plug cap 2.
Note: Be careful not to damage the radiator fins.
Warning! The hot radiator and the hot engine can burn you. Wait until the radiator and the engine are cool enough to touch.
Remove the spark plug with the special tool.
- 09930-10121 : Spark plug socket wrench set.
No.2 (rear) spark plug removal
Remove the seat. (7-4)
Lift and support the fuel tank. (5-7)
Remove the spark plug cap.
Remove the spark plug with the special tool.
- 09930-10121 : Spark plug socket wrench set.
Heat range
Check to see the heat range of the plug.
| Standard | Cold type | Hot type | |
| NGK | CR8E | CR9E | CR7E |
| DENSO | U24ESR-N | U27ESR-N | U22ESR-N |
Carbon deposit
Check to see if there are carbons deposit on the plugs. If carbon is deposited, remove it with a spark plug cleaner machine or carefully using a tool with a pointed end.
Spark plug gap
Measure the plug gap with a thickness gauge. If out of specification, adjust it to the following gap.
Spark plug gap A:
- Standard: 0.7-0.8 mm (0.028-0.031 in)
- 09900-20803: Thickness gauge.
Electrodes condition
Check to see the worn or burnt condition of the electrodes. If it is extremely worn or burnt, replace the plug. And also replace the plug if it has a broken insulator, damaged thread.
Caution! Confirm the thread size and reach when replacing the plug. If the reach is too short, carbon will be deposited on the screw portion of the plug hole and engine damage may result.
Spark plug and plug cap installation
Caution! Before using a spark plug wrench, carefully turn the spark plug by finger into the threads of the cylinder head to prevent damage the aluminum threads.
Install the spark plugs to the cylinder heads by finger tight, and then tighten them to the specified torque.
- Spark plug: 11 N·m (1.1 kgf·m, 8.0 lb·ft).
Note: When fitting the spark plug caps, front and rear, face the triangle mark A on the water-proof cover to each cylinder exhaust side.
