Yamaha XVS650H 2016 Owner's Manual page 52

Periodic maintenance and adjustment
1. Spark plug wrench
To check the spark plugs
1. Check that the porcelain insulator
around the center electrode on
each spark plug is a medium-to-
7
light tan (the ideal color when the
vehicle is ridden normally).
2. Check that all spark plugs in-
stalled in the engine have the
same color.
TIP
If any spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer check
the vehicle.
3. Check each spark plug for elec-
trode erosion and excessive car-
bon or other deposits, and replace
it if necessary.
Specified spark plug:
NGK/DPR7EA-9
DENSO/X22EPR-U9
4. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifi-
cation.
1. Spark plug gap
Spark plug gap:
0.8–0.9 mm (0.031–0.035 in)
7-10
To install a spark plug
1. Clean the surface of the spark
plug gasket and its mating surfa-
ce, and then wipe off any grime
from the spark plug threads.
2. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
Tightening torque:
Spark plug:
18 N·m (1.8 kgf·m, 13 lb·ft)
TIP
If a torque wrench is not available
when installing a spark plug, a good
estimate of the correct torque is 1/4–
1/2 turn past finger tight. However, the
spark plug should be tightened to the
specified torque as soon as possible.
3. Install the spark plug cap.