2007 YAMAHA YFM50R check engine

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utes, and then turn it off.
3. Place an oil pan under the engine to collect
the used oil.
4. Remove the engine oil filler cap, and then re-
move the engine oil drain bolt to drain the oil
from the crankcase.
5. Check the O-ring for damage and replace it if
necessary.
6. Install the engine oil drain bolt, and then tight-
en it to the specified torque.7. Add the specified amount of the recommend-
ed engine oil, and then install and tighten the
engine oil filler cap.CAUTION:
ECB00300

In order to prevent clutch slippage (since the
engine oil also lubricates the clutch), do not
mix any chemical additives. Do not use oils
with a diesel specification of “CD” or oils of
a higher quality than specified. In addition,
do not use oils labeled “ENERGY CONSERV-
ING II” or higher.

Make sure that no foreign material enters the
crankcase.
8. Start the engine, and then let it idle for several
1. Engine oil drain bolt
1

Tightening torque:
Engine oil drain bolt:
20 Nm (2.0 m·kgf, 14.5 ft·lbf)
Recommended oil:
See page 10-1.
Oil quantity:
0.80 L (0.85 US qt) (0.70 Imp.qt)

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minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
9. Turn the engine off, and then check the oil lev-
el and correct it if necessary.
EBU23403
Final gear oil
The final gear case must be checked for oil leak-
age before each ride. If any leakage is found, have
a Yamaha dealer check and repair the ATV. In ad-
dition, the final gear oil level must be checked and
the oil changed as follows at the intervals specified
in the periodic maintenance and lubrication chart.
To check the final gear oil level
1. Place the ATV on a level surface.
NOTE:

The final gear oil level must be checked on a cold
engine.
2. Remove the final gear oil filler cap, wipe the
dipstick off with a clean rag, insert it back into
the oil filler hole (without screwing it in), and
then remove it again to check the oil level.
NOTE:

The final gear oil should be between the minimum
and maximum level marks.
3. If the oil is at or below the minimum level mark,
add sufficient oil of the recommended type to
raise it to the correct level.
4. Insert the dipstick into the oil filler hole, and
then tighten the oil filler cap.
1. Final gear oil filler cap
2. Dipstick
3. Maximum level mark
4. Minimum level mark
2 3
4
1

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plode.
5. Squeeze the excess solvent out of the sponge
material and let it dry.
CAUTION:

ECB00440
Do not twist the sponge material when squeez-
ing it.
6. Check the sponge material and replace it if
damaged.
7. Apply a quality foam air filter oil to the sponge
material.
NOTE:

The sponge material should be wet but not drip-
ping.
8. Install the sponge material into the air filter el-
ement.
9. Place the air filter element in the original posi-
tion, and then hook the holder.
10. Install the air filter case cover by hooking the
holders onto the air filter case.
11. Install the panel by installing the bolts.
NOTE:

The air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated moreoften if the ATV is operated in extremely dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions.
CAUTION:

ECB00460

Make sure that the air filter element is prop-
erly seated in the air filter case.

Never operate the engine with the air filter el-
ement removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addition-
ally, operation without the air filter element
will affect carburetor jetting with subsequent
poor performance and possible engine over-
heating.
EBU27630
Cleaning the spark arrester
Be sure the exhaust pipe and muffler are cool be-
fore cleaning the spark arrester.
1. Remove the screws.

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EBU23940
Adjusting the carburetor
The carburetor should be checked and, if neces-
sary, adjusted at the intervals specified in the peri-
odic maintenance and lubrication chart. The
carburetor is an important part of the engine and
requires very sophisticated adjustment. Therefore,
most carburetor adjustments should be left to a
Yamaha dealer, who has the necessary profes-
sional knowledge and experience. The adjustment
described in the following section, however, may
be performed by the owner as part of routine main-
tenance.
CAUTION:

ECB00480
The carburetor has been set and extensively
tested at the Yamaha factory. Changing these
settings without sufficient technical knowl-
edge may result in poor performance of or
damage to the engine.
EBU24000
Adjusting the engine idling speed
The engine idling speed must be checked and, if
necessary, adjusted as follows at the intervals
specified in the periodic maintenance and lubrica-tion chart.
NOTE:

A diagnostic tachometer is needed to make this
adjustment.
1. Start the engine and warm it up.
NOTE:

The engine is warm when it quickly responds to the
throttle.
2. Attach the tachometer to the spark plug lead.
3. Check the engine idling speed and, if neces-
sary, adjust it to specification by turning the
throttle stop screw at the carburetor. To in-
crease the engine idling speed, turn the throt-
tle stop screw in direction (a), and to decrease
it, turn the screw in direction (b).

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NOTE:

If the specified idling speed cannot be obtained as
described above, have a Yamaha dealer make the
adjustment.
EBU27071
Checking the throttle cable free play
The throttle cable free play should be checked at
the intervals specified in the periodic maintenance
and lubrication chart.The throttle cable free play should measure 1.0–
3.0 mm (0.04–0.12 in) at the throttle lever. Period-
ically check the throttle cable free play and, if nec-
essary, have a Yamaha dealer adjust it.
EBU24060
Valve clearance
The valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance and lu-
brication chart.
1. Throttle stop screw
Engine idling speed:
1750–1850 r/min
1 (a) (b)

1. Throttle lever free play
1

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adjusting nut on the brake cable at the rear
wheel hub in direction (a), and to decrease it,
turn the nut in direction (b).
7. Tighten the locknut at the brake lever.
NOTE:

If the specified free play cannot be obtained as de-
scribed above or if the rear brake does not operate
correctly, have a Yamaha dealer check the internal
rear brake mechanism.WARNING
EWB02080
Operating with improperly serviced or adjust-
ed brakes could cause loss of braking ability,
which could lead to an accident.
After servicing:

Make sure the brakes operate smoothly and
that the free play is correct.

Make sure the brakes do not drag.
Replacement of brake components requires
professional knowledge. These procedures
should be performed by a Yamaha dealer.
EBU24900
Checking and lubricating the cables
The operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-
essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
1. Brake lever free play adjusting nut
1
(a)(b)

Recommended lubricant:
Engine oil

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EBU25791
Troubleshooting chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the ATV.
The engine does not start.
Have a Yamaha dealer
check the ATV.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the electrolyte level, recharge the
battery and check the lead connections.
DryWet
Open the throttle halfway and operate
the electric starter.

INDEX
A
Accessories and loading ................................................ 6-7
Air filter element, cleaning ............................................ 8-12
B
Battery .................................................................. 5-6
,
8-25
Brake lever free play, adjusting the front...................... 8-20
Brake lever free play (rear), adjusting .......................... 8-22
Brake lever, front ............................................................ 4-6
Brake lever, rear............................................................. 4-6
Brake levers, checking and lubricating......................... 8-24
Brakes, front and rear .................................................... 5-3
Brake shoes, checking the front and rear .................... 8-19
C
Cables, checking and lubricating ................................. 8-23
Carburetor, adjusting.................................................... 8-17
Chassis fasteners........................................................... 5-6
Choke ........................................................................... 4-10
Cleaning ......................................................................... 9-1
D
Drive select lever............................................................ 4-7
E
Engine break-in .............................................................. 6-5
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-17
Engine oil ............................................................... 5-3
,
8-8
Engine, starting a warm ................................................. 6-3Engine stop switch ......................................................... 4-2
Engine stop switch with lanyard ..................................... 4-2
F
Final gear oil..........................................................5-3
,
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Fuel .........................................................................4-8
,
5-3
Fuel cock ........................................................................ 4-9
Fuel tank cap.................................................................. 4-7
Fuse, replacing............................................................. 8-28
H
Handlebar switches ........................................................ 4-2
I
Identification numbers .................................................. 11-1
Indicator light .................................................................. 4-1
Instruments, lights and switches .................................... 5-6
K
Key identification number ............................................. 11-1
Knuckle shafts, lubricating ........................................... 8-24
L
Label locations ............................................................... 2-1
M
Main switch .................................................................... 4-1
Model label ................................................................... 11-2
N
Neutral indicator light ..................................................... 4-1
O
Owner’s manual and tool kit ........................................... 8-1