Checking The Spark Plug - Yamaha JOGR JOGK CS50Z Owner's Manual

PERIODIC MAINTENANCE AND MINOR REPAIR

Checking the spark plug

The spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause
any spark plug to slowly erode, the
spark plug should be removed and
checked in accordance with the
periodic maintenance and lubrication
chart. In addition, the condition of the
spark plug can reveal the condition of
the engine.
To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as
6
shown, with the spark plug
wrench included in the owner's
tool kit.
To check the spark plug
1. Check that the porcelain insula-
tor around the center electrode of
the spark plug is a medium-to-
light tan (the ideal color when the
vehicle is ridden normally).
NOTE:
If the spark plug shows a distinctly
different color, the engine could be
defective. Do not attempt to diagnose
EAU19602 such problems yourself. Instead, have
a Yamaha dealer check the vehicle.
2. Check the spark plug for electro-
de erosion and excessive carbon
or other deposits, and replace it if
necessary.
Specified spark plug:
BR8HS/NGK
To install the spark plug
1. Distance between electrodes
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to spe-
cification.
Spark plug gap:
0,6 ~ 0,7 mm (0,24 ~ 0,27in)
2. Clean the surface of the spark
3. Install the spark plug with the
NOTE:
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. Howe-
ver, the spark plug should be tighte-
ned to the specified torque as soon
as possible.
4. Install the spark plug cap.
6-5
plug gasket and its mating surfa-
ce, and then wipe off any grime
from the spark plug threads.
spark plug wrench, and then
tighten it to the specified torque.
Tightening torque:
Spark plug:
20 Nm (2,0 m•kgf, 14,6 ft•lbf)