Suzuki VS1400 Owner's Manual page 91

NGK DENSO
DPR7EA-9 X22EPR-U9 If the standard plug
DPR8EA-9 X24EPR-U9 Standard
DPR9EA-9 X27EPR-U9 If the standard plug
NOTE: If the above-named plugs are
not available, consult your authorized
Suzuki dealer.
NOTE: This motorcycle uses resistor-
type spark plug to avoid jamming elec-
tronic parts. Improper spark plug selec-
tion may cause electronic interference
with your motorcycle ignition system,
resulting in motorcycle performance
problems. Use recommended spark
plug.
Remarks
tends to run cold
tends to run hot
7-23
CAUTION
A crossthreaded or overtightened spark
plug will damage the aluminum threads of
the cylinder head.
Carefully turn the spark plug by hand
into the threads until it is finger tight. If
the spark plug is new, tighten it with a
wrench about 1/2 turn past finger tight.
If you are reusing the old spark plug,
tighten it with a wrench about 1/8 turn
past finger tight.
CAUTION
Dirt can damage your engine if it enters an
open spark plug hole.
Cover the spark plug hole whenever the
spark plug is removed.