Suzuki VL800 Service Manual page 21

• Remove the spark plug caps.
• Remove the spark plugs with a spark plug wrench.
HEAT RANGE
• Check spark plug heat range by observing electrode color. If
the electrode of the spark plug is wet appearing or dark color,
replace the spark plug with hotter type one. If it is white or glazed
appearing, replace the spark plug with colder type one.
Standard
Colder type
NOTE:
"R" type spark plug has a resistor located at the center electrode
to prevent radio noise.
CARBON DEPOSITS
• Check carbon deposits on the spark plug.
• If carbon is deposited, remove it using a spark plug cleaner
machine or carefully use a tool with a pointed end.
SPARK PLUG GAP
• Measure the spark plug gap with a thickness gauge.
• Adjust the spark plug gap if necessary.
" Spark plug gap:
Standard: 0.8 – 0.9 mm (0.031 – 0.036 in)
# 09900-20803: Thickness gauge
ELECTRODE'S CONDITION
• Check the condition of the electrode.
• If it is extremely worn or burnt, replace the spark plug. Replace
the spark plug if it has a broken insulator, damaged thread, etc.
$
Check the thread size and reach when replacing the spark
plug. If the reach is too short, carbon will be deposited
on the screw portion of the spark plug hole and engine
damage may result.
NGK DENSO
DPR7EA-9 X22EPR-U9
DPR8EA-9 X24EPR-U9
PERIODIC MAINTENANCE 2-5
Gap:
0.8 – 0.9 mm
(0.031 – 0.036 in)