The standard spark plug is shown in the table. The spark plugs should be replaced in accordance with the Periodic Maintenance Chart.
Spark plug removal should be done only by a competent mechanic following the instructions in the Service Manual.
Spark Plug

A. Plug Gap
Coolant Filling
Evaporative Emission Control System (California
model only)Air Cleaner
A clogged air cleaner restricts the engine’s
air intake, increasing fuel consumption,
reducing engine power, and
causing spark plug fouling.
This motorcycle’s air cleaner element
consists of a wet paper filter, which cannot
be cleaned.
The air cleaner element must be replaced
in acco ...
Spark Plug Condition Inspection
Remove the spark plugs (see Spark Plug Replacement in
the Periodic Maintenance chapter).
Visually inspect the spark plugs.
If the spark plug center electrode [A] and/or side electrode
[B] are corroded or damaged, or if the insulator [C]
is cracked, replace the plug.
If the spark plug is ...
For Primary Fuel Injectors
Remove the air cleaner housing (see Air Cleaner Housing
Removal).
Disconnect the injector connector and connect the harness
adapter [A] between these connectors as shown in
the figure.
Main Harness [B]
Primary Fuel Injector #1 [C]
Special Tool - Measuring Adapter: 57001-1700
...