Suzuki VZ800 Service Manual page 22

2-6 PERIODIC MAINTENANCE
No. 2 (REAR) SPARK PLUG REMOVAL
• Remove the rear and front seats. (8-3)
• Remove the fuel tank. (6-3)
• Remove the spark plug cap.
• Remove the spark plug with a spark plug wrench.
HEAT RANGE
• Check to see the heat range of the plug.
Standard
NGK DPR7EA-9
DENSO X22EPR-U9
CARBON DEPOSIT
• Check to see if there are carbon deposits on the plugs. If car-
bon 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 specifi-
cation, adjust it to the following gap.
 09900-20803: Thickness gauge
 Spark plug gap A
Standard: 0.8 – 0.9 mm (0.031 – 0.035 in)
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.

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 dam-
age may result.
Cold type
DPR8EA-9
X24EPR-U9