2004 YAMAHA BANSHEE 350 spark plugs

8-39
EBU00287
Spark plug inspection
The spark plugs are important engine compo-
nents and are easy to inspect. The condition of
the spark plugs can indicate the condition of the
engine.
Normally, all spark plugs from the same engine
should have the same color on the white porce-
lain insulator around the center electrode. The
ideal color at this point is a medium to light tan
color for a machine that is being ridden normal-
ly. If one spark plug shows a distinctly different
color, there could be something wrong with the
engine.
Do not attempt to diagnose such problems your-
self. Instead, take the machine to a Yamaha
dealer. You should periodically remove and
inspect the spark plugs because heat and
deposits will cause any spark plug to slowly
break down and erode. If electrode erosion
becomes excessive, or if carbon and other
deposits are excessive, you should replace the
spark plug with the specified plug.

8-117
EBU00440
Troubleshooting chart
Starting problems or poor engine performance
Check fuel flow
1. Fuel
Check if there is
fuel in the fuel
tank
2. Compression
Kick the kick starter
to see if there is
compression
3. Ignition
Remove plugs and
check electrodes
WetWipe clean with
dry cloth
DryAttach plug cap and
ground to chassisKick the kick
starter stronglySpark weak
Spark goodIgnition system normal
No spark
Ask a Yamaha dealer to inspect
Adjust plug gap or
replace plug(s)
There is compressonCompression normal
Ask a Yamaha dealer to inspectNo compression
There is fuelTurn the fuel
cock to “OFF”
Remove the
fuel pipeNo fuelFuel cock clogged
Some fuelTurn the fuel
cock to “RES”Restart engine
No fuelSupply fuel
Clean fuel cock

9-1
EBU00416
CLEANING AND STORAGE
A. CLEANING
Frequent, thorough cleaning of your machine
will not only enhance its appearance but will
improve its general performance and extend the
useful life of many components.
1. Before cleaning the machine:
a. Block off the end of the exhaust pipe to
prevent water entry. A plastic bag and
strong rubber band may be used.
b. Make sure the spark plugs and all filler
caps are properly installed.
2. If the engine case is excessively greasy,
apply degreaser with a paint brush. Do not
apply degreaser to the chain, sprockets or
wheel axles.
3. Rinse the dirt and degreaser off with a gar-
den hose. Use only enough pressure to do
the job.

9-7
EBU00529
B. STORAGE
Long term storage (60 days or more) of your
machine will require some preventive proce-
dures to guard against deterioration. After thor-
oughly cleaning the machine, prepare for stor-
age as follows:
1. Drain the fuel tank, fuel lines and carbure-
tor float bowls.
2. Remove the spark plugs, pour about one
tablespoon of SAE 10W30 or 20W40
motor oil in the spark plug holes and rein-
stall the spark plugs. Ground the spark
plug wires and turn the engine over several
times to coat the cylinder walls with oil.
3. Clean the drive chain thoroughly and lubri-
cate it. (See page 8-95 for details.)
Reinstall the chain or store it in a plastic
bag tied to frame for safekeeping.
4. Lubricate all control cables.