2003 YAMAHA BIG BEAR PRO 400 engine

8-99
EBU00440Troubleshooting chart1. Fuel
Check if there is fuel
in the fuel tank.There is fuel.Turn the fuel
cock to “OFF”.Remove the fuel pipe
from the fuel cock. Fuel cock
clogged.
Clean fuel
cock. Some fuel.Turn the fuel
cock to “RES”.Restart engine.
No fuel.
Supply fuel
2. Compression
Use electric starter
to see if there is
compression.There is compression.
No compression.
3. Ignition
Remove plug and
check electrodes.WetWipe clean with
dry cloth.
DryAttach plug cap and
ground to chassis.Use the
electric starter.Spark good.Ignition system
normal.
Spark weak.
Adjust plug gap
or replace plug. No spark.
Ask a Yamaha dealer to inspect. 4. Battery
Use electric starter.Engine turns over
quickly.Battery good.
Engine turns over
slowly.
Check fuel
flow. Turn the fuel
cock to “ON”.
Compression normal.Ask a Yamaha dealer to inspect.
Recharge, check
connections.
No fuel.
EE.book Page 99 Monday, June 18, 2001 10:18 AM

9-1
EBU00420
1-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 pre-
vent water entry. A plastic bag and strong
rubber band may be used.
b. Make sure the spark plug and all filler caps
are properly installed.
2. If the engine case is excessively greasy, ap-
ply degreaser with a paint brush. Do not ap-
ply degreaser to the wheel axles.
3. Rinse the dirt and degreaser off with a garden
hose. Use only enough pressure to do the
job.
EE.book Page 1 Monday, June 18, 2001 10:18 AM

9-5
7. Automotive type wax may be applied to all
painted and chrome plated surfaces. Avoid
combination cleaner-waxes. Many contain
abrasives which may mar the paint or protec-
tive finish.
When finished, start the engine and let it idle
for several minutes.
WARNING
Wet brakes may have reduced stopping ability,
increasing the chance of an accident. Test the
brakes after washing. Apply the brakes several
times at slow speeds to let friction dry out the
linings.
EE.book Page 5 Monday, June 18, 2001 10:18 AM

9-7
EBU00427
B. STORAGE
Long term storage (60 days or more) of your ma-
chine will require some preventive procedures to
guard against deterioration. After thoroughly
cleaning the machine, prepare for storage as fol-
lows:
1. Fill the fuel tank with fresh fuel and add fuel
stabilizer (if available).NOTE:Use of fuel stabilizer eliminates the need to drain
the fuel system. Consult a Yamaha dealer if the
fuel system is to be drained instead.2. Remove the spark plug, pour about one ta-
blespoon of SAE 10W30 or 20W40 motor oil
in the spark plug hole and reinstall the spark
plug. Ground the spark plug wire and turn the
engine over several times to coat the cylinder
wall with oil.
3. Lubricate all control cables.
4. Block up the frame to raise all wheels off the
ground.
EE.book Page 7 Monday, June 18, 2001 10:18 AM

10-1
EBU00428
1-SPECIFICATIONS
Model YFM400FP/YFM400FW
Dimensions:
Overall length 1,956 mm
Overall width 1,155 mm
Overall height 1,144 mm
Seat height 845 mm
Wheelbase 1,210 mm
Minimum ground clearance 215 mm
Minimum turning radius 3,500 mm
Basic weight:
With oil and full fuel tank 286 kg
Engine:
Engine type Air-cooled 4-stroke, SOHC
Cylinder arrangement Forward-inclined single cylinder
Displacement 386 cm
3
Bore
× stroke 83.0 ×
71.5 mm
Compression ratio 8.6:1
Starting system Electric and recoil starter
Lubrication system Wet sump
EE.book Page 1 Monday, June 18, 2001 10:18 AM

10-2
10
Noise and vibration level:
Noise level (77/311/EEC) 87.1 dB (A)
Vibration on seat (EN1032, ISO5008) Not exceed 0.5 m/s
2
Vibration on handlebar (EN1032, ISO5008) Not exceed 2.5 m/s
2
Engine oil/Transfer gear oil:
Type
Recommended engine oil classification: API Service SE, SF, SG type or higherModel YFM400FP/YFM400FW
-20˚-10˚0˚
10˚20˚30˚40˚50˚C
10W/30
15W/4020W/4020W/50
10W/40
5W/30
CAUTION:
Be sure to use motor oils that do not contain anti-
friction modifiers. Passenger car motor oils (often
labeled “Energy Conserving II”) contain anti-fric-
tion additives which will cause clutch and/or
starter clutch slippage, resulting in reduced com-
ponent life and poor engine performance.
EE.book Page 2 Monday, June 18, 2001 10:18 AM

10-3
Quantity:
Periodic oil change (engine oil): 2.4 L
Periodic oil change
(engine oil with oil filter replacement): 2.5 L
Periodic oil change
(engine oil and transfer gear oil with
oil filter replacement):3.1 L
Transfer gear case oil 0.3 L
Total amount 3.4 L
Final gear oil:
Type SAE 80 API “GL-4” Hypoid gear oil
Quantity
Periodic oil change 0.19 L
Total amount 0.25 L
Air filter: Wet type element
Differential gear oil:
Type SAE80 API “GL-4” Hypoid gear oil
Quantity:
Periodic oil change 0.47 L
Total amount 0.5 LModel YFM400FP/YFM400FW
EE.book Page 3 Monday, June 18, 2001 10:18 AM