Checking The Spark Plugs - Yamaha YZF-R1S Owner's Manual

Panels B and D
To remove one of the panels
1. Remove the rider seat. (See page
3-19.)
2. Remove the screw, and then re-
move the panel as shown.
1. Screw
2. Panel B
To install the panel
1. Place the panel in its original posi-
tion, and then install the screw.
PERIODIC MAINTENANCE AND MINOR REPAIR
EAU33990
2. Install the rider seat.

Checking the spark plugs

The spark plugs are important engine
components, which should be checked
periodically, preferably by a Yamaha
dealer. Since heat and deposits will
cause any spark plug to slowly erode,
they should be removed and checked
in accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plugs can re-
veal the condition of the engine.
The porcelain insulator around the cen-
ter electrode of each spark plug should
be a medium-to-light tan (the ideal color
when the vehicle is ridden normally),
and all spark plugs installed in the en-
gine should have the same color. If any
spark plug shows a distinctly different
color, the engine could be defective. Do
not attempt to diagnose such problems
yourself. Instead, have a Yamaha deal-
er check the vehicle.
If a spark plug shows signs of electrode
erosion and excessive carbon or other
deposits, it should be replaced.
6-7
Specified spark plug:
NGK/CR9EK
EAU19651
6