Checking The Spark Plugs - Yamaha YZF-R1 Owner's Manual

To install a cowling
1. Insert the projection into the slot,
and then slide the cowling back-
ward.
2
3
1
1. Cowling C
2. Slot
3. Projection
2
3
1
1. Cowling D
2. Slot
3. Projection
PERIODIC MAINTENANCE AND ADJUSTMENT
2. Place the cowling in its original po-
sition, and then install the quick
fastener screws.
3. Install cowling A or B.
6-10

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 operating im-
properly. Do not attempt to diagnose
such problems yourself. Instead, have
a Yamaha dealer check the vehicle.
If a spark plug shows signs of electrode
erosion and excessive carbon or other
deposits, it should be replaced.
Specified spark plug:
NGK/LMAR9E-J
EAU19652
6