HOME 9. See Figure 1-59 . Compare your observations of the plug deposits with the descriptions provided. 12. Check condition of threads on cylinder head and plug. If necessary to remove deposits, apply penetrating oil and clean out with a thread chaser. a. A wet, black and shiny deposit on plug base, elec- trodes and ceramic insulator tip indicates an oil fouled plug. The condition may be caused by one or more of the following: worn pistons, worn piston rings, worn valves, worn valve guides, worn valve seals, a weak battery or a faulty ignition system. sm00099 1 2 b.
A dry, fluffy or sooty black deposit indicates an air- fuel mixture that is too rich, engine idling for excessive periods of time and/or enrichener usage for excessive periods of time. c. A light brown, glassy deposit indicates an overheated plug. This condition may be accompanied by cracks in the insulator or by erosion of the electrodes and is caused by an air-fuel mixture that is too lean, a hot- running engine, valves not seating or improper ignition timing. The glassy deposit on the spark plug is a conductor when hot and may cause high-speed mis- firing. A plug with eroded electrodes, heavy deposits or a cracked insulator must be replaced. 3 4 d.
A plug with a white, yellow, tan or rusty brown powdery deposit indicates balanced combustion. Clean off spark plug deposits at regular intervals. 1. Oil-fouled 2. Sooty black deposits 3. Overheated 4. Balanced combustion Compressed air can pierce the skin and flying debris from compressed air could cause serious eye injury. Wear safety glasses when working with compressed air. Never use your hand to check for air leaks or to determine air flow rates. (00061a) Figure 1-59.Typical Spark Plug Deposits 10. If the plugs require cleaning between tune-ups, proceed as follows: INSTALLATION a. Degrease firing end of spark plug using ELECTRICAL CONTACT CLEANER. Dry plug with compressed air. 1.
Apply LOCTITE® ANTI-SEIZE to plug threads. Install and tighten to 23 Nm (17 ft-lbs). b. Use a thin file to flatten spark plug electrodes. A spark plug with sharp edges on its electrodes requires 25- 40% less firing voltage than one with rounded edges. 2. Install coil and boot assembly over spark plug with wiring connector facing rear of motorcycle. c. If the plugs cannot be cleaned, replace with No. 10R12A spark plugs. 3. Insert coil fasteners with long fastener used on left side. Tighten to 9.7 Nm (86 in-lbs ). 11. Check electrode gap with a wire-type feeler gauge. Bend the outside of the electrode so only a slight drag on the gauge is felt when passing it between electrodes.
Proper gap measurement is 0.89 mm (0.035 in.). 4. Mate connectors [83R] and [83F]. 5. Install battery after installing front plug and coil. See 1.9 BATTERY MAINTENANCE . 6. Install rear plug and coil and install coolant overflow bottle. 7. Install air box assembly. See 1.5 AIR CLEANER AND EXHAUST SYSTEM . 1-48 2009 VRSC Service: Maintenance