engine YAMAHA TTR50 2008 Owner's Manual

PERIODIC MAINTENANCE AND MINOR REPAIR
6-5
6
EAU19612
Checking the spark plug The spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as shown,
with a spark plug wrench available
at a Yamaha dealer.To check the spark plug
1. Check that the porcelain insulator
around the center electrode of the
spark plug is a medium-to-light tan
(the ideal color when the vehicle is
ridden normally).
NOTE:
If the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer checkthe vehicle.2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
To install the spark plug
1. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifica-
tion.
1. Spark plug cap
1. Spark plug wrench
Specified spark plug:
NGK/CR7HSA1. Spark plug gapSpark plug gap:
0.6–0.7 mm (0.024–0.028 in)
U1P682E0.book Page 5 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-6
6 2. Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
NOTE:
If a torque wrench is not available when
installing a spark plug, a good estimate
of the correct torque is 1/4–1/2 turn
past finger tight. However, the spark
plug should be tightened to the speci-fied torque as soon as possible.
4. Install the spark plug cap.
EAU39840
Engine oil The engine oil level should be checked
before each ride. In addition, the oil
must be changed at the intervals spec-
ified in the periodic maintenance and
lubrication chart.
To check the engine oil level
1. Place the motorcycle on a level
surface and hold it in an upright po-
sition.NOTE:Make sure that the motorcycle is posi-
tioned straight up when checking the oil
level. A slight tilt to the side can result ina false reading.
2. Start the engine, warm it up for
several minutes, and then turn it
off.
3. Wait a few minutes until the oil set-
tles, remove the oil filler cap, wipe
the dipstick clean, insert it back
into the oil filler hole (without
screwing it in), and then remove it
again to check the oil level.
NOTE:
The engine oil should be between theminimum and maximum level marks.
4. If the engine oil is at or below the
minimum level mark, add sufficient
oil of the recommended type to
raise it to the correct level.
5. Insert the dipstick into the oil filler
hole, and then tighten the oil filler
cap.
Tightening torque:
Spark plug:
12.5 Nm (1.25 m·kgf, 9.0 ft·lbf)
1. Engine oil filler cap
2. Dipstick
3. Maximum level mark
4. Minimum level mark
U1P682E0.book Page 6 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-7
6To change the engine oil
1. Start the engine, warm it up for
several minutes, and then turn it
off.
2. Place an oil pan under the engine
to collect the used oil.
3. Remove the engine oil filler cap
and drain bolt to drain the oil from
the crankcase.
4. Install the engine oil drain bolt, and
then tighten it to the specified
torque.5. Add the specified amount of the
recommended engine oil, and then
install and tighten the engine oil fill-
er cap.
CAUTION:
ECA11620


In order to prevent clutch slip-
page (since the engine oil also
lubricates the clutch), do not
mix any chemical additives. Do
not use oils with a diesel speci-
fication of “CD” or oils of a high-
er quality than specified. In
addition, do not use oils labeled
“ENERGY CONSERVING II” or
higher.


Make sure that no foreign mate-rial enters the crankcase.
6. Start the engine, and then let it idle
for several minutes while checking
it for oil leakage. If oil is leaking, im-
mediately turn the engine off and
check for the cause.7. Turn the engine off, and then
check the oil level and correct it if
necessary.
1. Engine oil drain boltTightening torque:
Engine oil drain bolt:
20 Nm (2.0 m·kgf, 14 ft·lbf)
1
Recommended engine oil:
See page 8-1.
Oil change quantity:
0.80 L (0.85 US qt) (0.70 Imp.qt)
U1P682E0.book Page 7 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-9
6
NOTE:The sponge material should be wet butnot dripping.
6. Insert the mesh and the sponge
material into the air filter case.CAUTION:
ECA15571


Make sure that the mesh and the
sponge material are properly
seated in the air filter case.


The engine should never be op-
erated without the mesh and the
sponge material installed, oth-
erwise the piston(s) and/or cyl-
inder(s) may becomeexcessively worn.
7. Install the air filter case cover by in-
stalling the screws.
To clean the air filter check hose
1. Check the hose at the bottom of
the air filter case for accumulated
dirt or water.2. If dirt or water is visible, remove
the hose, clean it, and then install
it.
EAU40421
Cleaning the spark arrester The spark arrester should be cleaned
at the intervals specified in the periodic
maintenance and lubrication chart.
WARNING
EWA10980


Always let the exhaust system
cool prior to touching exhaust
components.


Do not start the engine whencleaning the exhaust system.
NOTE:Make sure to select a well-ventilated
area free of combustible materials toclean the spark arrester.
1. Remove the tailpipe by removing
the bolts, and then pulling it out of
the muffler.
Recommended oil:
Yamaha foam air filter oil or other
quality foam air filter oil
1. Air filter check hose
U1P682E0.book Page 9 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-10
6 2. Tap the tailpipe lightly, and then
use a wire brush to remove any
carbon deposits from the spark ar-
rester portion of the tailpipe and in-
side of the tailpipe housing.3. Insert the tailpipe into the muffler,
and then install and tighten the
bolts to the specified torque.
NOTE:
Make sure to align the bolt holes wheninserting the tailpipe.
EAU39930
Adjusting the carburetor The carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most car-
buretor adjustments should be left to a
Yamaha dealer, who has the neces-
sary professional knowledge and expe-
rience. The adjustment described in the
following section, however, may be ser-
viced by the owner as part of routine
maintenance.CAUTION:
ECA10550
The carburetor has been set and ex-
tensively tested at the Yamaha fac-
tory. Changing these settings
without sufficient technical knowl-
edge may result in poor perfor-mance of or damage to the engine.
1. Bolt
2. Tailpipe
1. Spark arrester
1
Tightening torque:
Tailpipe bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
U1P682E0.book Page 10 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-11
6
EAU21360
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 lubrication
chart.NOTE:
A diagnostic tachometer is needed tomake this adjustment.
1. Attach the tachometer to the spark
plug lead.
2. Start the engine and warm it up for
several minutes at 1000–2000
r/min while occasionally revving it
to 4000–5000 r/min.NOTE:The engine is warm when it quickly re-sponds to the throttle.
3. Check the engine idling speed
and, if necessary, adjust it to spec-
ification by turning the throttle stop
screw. To increase the engine
idling speed, turn the screw in di-rection (a). To decrease the en-
gine idling speed, turn the screw in
direction (b).
NOTE:
If the specified idling speed cannot be
obtained as described above, have aYamaha dealer make the adjustment.
EAU21370
Adjusting the throttle cable
free play The throttle cable free play should mea-
sure 3.0–5.0 mm (0.12–0.20 in) at the
throttle grip. Periodically check the
throttle cable free play and, if neces-
sary, adjust it as follows.NOTE:The engine idling speed must be cor-
rectly adjusted before checking and ad-justing the throttle cable free play.
1. Loosen the locknut.
1. Throttle stop screwEngine idling speed:
1600–1800 r/min
1
(a) (b)
1. Throttle cable free play
U1P682E0.book Page 11 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-12
6 2. To increase the throttle cable free
play, turn the adjusting nut in direc-
tion (a). To decrease the throttle
cable free play, turn the adjusting
nut in direction (b).
3. Tighten the locknut.
EAU21401
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 intervals specified in the periodic
maintenance and lubrication chart.
EAU39820
Tires To maximize the performance, durabil-
ity, and safe operation of your motor-
cycle, note the following points
regarding the specified tires.
Tire air pressure
The tire air pressure should be checked
and, if necessary, adjusted before each
ride.
WARNING
EWA14380


The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the temperature
of the tires equals the ambient
temperature).


The tire air pressure must be ad-
justed in accordance with the
weight of the rider, the riding
speed, and the riding condi-tions.
1. Locknut
2. Throttle cable free play adjusting nut
2 (a)
(b) 1
Standard tire air pressure:
Front:
100 kPa (15 psi) (1.00 kgf/cm²)
Rear:
100 kPa (15 psi) (1.00 kgf/cm²)
U1P682E0.book Page 12 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-18
6 2. To tighten the drive chain, turn the
adjusting nut at each end of the
swingarm in direction (a). To loos-
en the drive chain, turn the adjust-
ing nut at each end of the
swingarm in direction (b), and then
push the rear wheel forward.
NOTE:Using the alignment marks on each
side of the swingarm, make sure that
both adjusting nuts are in the same po-sition for proper wheel alignment.
CAUTION:
ECA10570
Improper drive chain slack will over-
load the engine as well as other vital
parts of the motorcycle and can lead
to chain slippage or breakage. To
prevent this from occurring, keep
the drive chain slack within thespecified limits.
3. Tighten both locknuts and the axle
nut to the specified torques.4. Adjust the brake pedal free play.
(See page 6-16.)
1. Brake pedal free play adjusting nut
2. Drive chain slack adjusting nut
3. Locknut
1
2
3
1. Axle nut
2. Locknut
3. Drive chain slack adjusting nut
4. Alignment marks
1(b) 4(a)
2
3
Tightening torques:
Locknut:
7.0 Nm (0.7 m·kgf, 5.1 ft·lbf)
Axle nut:
60 Nm (6.0 m·kgf, 43 ft·lbf)
U1P682E0.book Page 18 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-19
6
EAU23013
Cleaning and lubricating the
drive chain The drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly wear
out, especially when riding in dusty or
wet areas. Service the drive chain as
follows.CAUTION:
ECA10581
The drive chain must be lubricated
after washing the motorcycle andriding in the rain.
1. Remove all dirt and mud from the
drive chain with a brush or cloth.NOTE:For a thorough cleaning, have a
Yamaha dealer remove the drive chainand soak it in solvent.
2. Spray Yamaha Chain and Cable
Lube or a high-quality spray-type
drive chain lubricant on both sides
and on the middle of the chain,making sure that all side plates
and rollers have been sufficiently
oiled.
EAU23091
Checking and lubricating the
cables The operation of all control cables and
the condition of the cables should be
checked before each ride, and the ca-
bles and cable ends should be lubricat-
ed if necessary. If a cable is damaged
or does not move smoothly, have a
Yamaha dealer check or replace it.
WARNING
EWA10710
Damage to the outer housing of ca-
bles may result in internal rusting
and cause interference with cable
movement. Replace damaged ca-
bles as soon as possible to preventunsafe conditions.Recommended lubricant:
Yamaha Chain and Cable Lube or
engine oil SAE 10W-30
U1P682E0.book Page 19 Wednesday, May 23, 2007 9:34 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-22
6
CAUTION:
ECA10590
If any damage is found or the front
fork does not operate smoothly,
have a Yamaha dealer check or re-pair it.
EAU23280
Checking the steering Worn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as fol-
lows at the intervals specified in the pe-
riodic maintenance and lubrication
chart.
1. Place a stand under the engine to
raise the front wheel off the
ground.
WARNING
EWA10750
Securely support the vehicle so thatthere is no danger of it falling over.
2. Hold the lower ends of the front
fork legs and try to move them for-
ward and backward. If any free
play can be felt, have a Yamaha
dealer check or repair the steering.
U1P682E0.book Page 22 Wednesday, May 23, 2007 9:34 AM