2002 YAMAHA BEAR TRACKER 250 engine

8-21 1. Oil gallery bolt 2. Cloth
1. Boulon de rampe de graissage 2. Chiffon
1. Tornillo del conducto de aceite 2. Trapo
Oil pressure check
1. Put a cloth around the cylinder.
2. Slightly loosen the oil gallery bolt in the cylin-
der head.
3. Start the engine and keep it idling until oil be-
gins to seep from the oil gallery. If no oil
comes out after one minute, turn the engine
off so it will not seize and find the cause.
4. Start the engine and check the oil pressure.
5. After checking, tighten the oil gallery bolt to
the specified torque.CAUTION:_ Be sure to inspect the oil pressure after replac-
ing the engine oil. _
Tightening torque:
Oil gallery bolt:
7 Nm (0.7 m·kgf)
EE.book Page 21 Monday, June 25, 2001 2:27 PM

8-29
EBU00870
Spark plug inspection
The spark plug is an important engine component
and is easy to inspect. The condition of the spark
plug can indicate the condition of the engine.
For example, a very white center electrode porce-
lain color could indicate an intake air leak or carbu-
retion problem for that cylinder. Do not attempt to
diagnose such problems yourself.
Instead, take the ATV to a Yamaha dealer. You
should periodically remove and inspect the spark
plug because heat and deposits will cause the
spark plug to slowly break down and erode. If elec-
trode erosion becomes excessive, you should re-
place the spark plug with one of the proper type.
Standard spark plug:
DR7EA (NGK)
EE.book Page 29 Monday, June 25, 2001 2:27 PM

8-35
3. Pull out the air filter element.
4. Separate the foam cover from the air filter el-
ement.
5. Tap the element lightly to remove most of the
dust and dirt. Blow out the remaining dirt with
compressed air. If the element is damaged,
replace it.
6. Wash the foam cover gently but thoroughly in
water or solvent.
WARNING
_ When using solvent to clean the foam cover,
always use parts cleaning solvent. Never use
low flash point solvents or gasoline to clean
the foam cover because the engine could
catch fire or explode. _7. Squeeze the excess solvent out of the filter
and let it dry.CAUTION:_

Do not twist the foam cover when squeez-
ing it.


Do not add oil to the foam cover.
_8. Inspect the foam cover. If damaged, replace
it.
EE.book Page 35 Monday, June 25, 2001 2:27 PM

8-37 1. Air filter element 2. Foam cover
1.Élément du filtre à air 2. Cache en mousse
1. Elemento filtrante 2. Forro de espuma
9. Reinstall the foam cover to the air filter ele-
ment.
10. Reinstall the air filter assembly and parts re-
moved for access.NOTE:_ The air filter element should be cleaned every 20 ~
40 hours. It should be cleaned more often if the
machine is operated in extremely dusty areas.
Each time filter element maintenance is per-
formed, check the air inlet to the filter case for ob-
structions. Check the air cleaner rubber joint to the
carburetor and manifold fittings for an airtight seal.
Tighten all fittings securely to avoid the possibility
of unfiltered air entering the engine. _CAUTION:_ Never operate the engine with the air filter ele-
ment removed. This will allow unfiltered air to
enter, causing rapid engine wear and possible
engine damage. Additionally, operation with-
out the filter element will affect carburetor jet-
ting with subsequent poor performance and
possible engine overheating. _
EE.book Page 37 Monday, June 25, 2001 2:27 PM

8-39
EBU00296
Carburetor adjustment
The carburetor is a vital part of the engine and re-
quires very sophisticated adjustment. Most adjust-
ing should be left to a Yamaha dealer who has the
professional knowledge and experience to do so.
However, the idling speed may be performed by
the owner as a part of the usual maintenance rou-
tine.CAUTION:
The carburetor was set at the Yamaha factory
after many tests. If the settings are disturbed
by someone without sufficient technical
knowledge, poor engine performance and
damage may result.
EE.book Page 39 Monday, June 25, 2001 2:27 PM

8-41 1. Throttle stop screw
1. Vis d’arrêt de l’accélérateur
1. Tornillo de tope del acelerador
EBU00301
Idle speed adjustmentNOTE:A diagnostic tachometer must be used for this pro-
cedure.1. Start the engine and warm it up for a few min-
utes at approximately 1,000 to 2,000 r/min.
Occasionally rev the engine to 4,000 to
5,000 r/min. The engine is warm when it
quickly responds to the throttle.
2. Connect the tachometer and set the idle to
the specified idling speed by adjusting the
throttle stop screw. Turn the screw in to in-
crease engine speed, and out to decrease
engine speed.
Specified idle speed:
1,400 ~ 1,500 r/min
EE.book Page 41 Monday, June 25, 2001 2:27 PM

8-43 1. Adjusting bolt 2. Locknut a. 3 ~ 5 mm
1. Boulon de réglage 2. Contre-écrou
1. Perno de ajuste 2. Contratuerca
EBU00303
Valve clearance adjustment
The correct valve clearance changes with use, re-
sulting in improper fuel/air supply or engine noise.
To prevent this, the valve clearance must be ad-
justed regularly. This adjustment however, should
be left to a professional Yamaha service techni-
cian.
EBU00307
Throttle lever adjustmentNOTE:Adjust the engine idling speed before adjusting the
throttle lever free play.1. Loosen the locknut.
2. Turn the adjusting bolt until the throttle lever
free play is 3 ~ 5 mm.
3. Tighten the locknut.
EE.book Page 43 Monday, June 25, 2001 2:27 PM

8-63
EBU00570
Cable inspection and lubrication
WARNING
_ Inspect cables frequently and replace if dam-
aged. Corrosion can result when the outer cov-
ering of control cables becomes damaged.
Cables can also become frayed or kinked. Op-
eration of controls could be restricted, which
could cause an accident or injury. _Lubricate the inner cables and the cable ends. If
the cables do not operate smoothly, ask a Yamaha
dealer to replace them.
Recommended lubricant:
Engine oil
EE.book Page 63 Monday, June 25, 2001 2:27 PM