2006 YAMAHA TTR50 check engine

3 - 8
INSPADJ
4. Check:
Oil level
Oil level should be between maximum a
and minimum b marks.
Oil level is low → Add oil to proper level.
NOTE:
Wait a few minutes until the oil settles before
inspecting the oil level.
 When inspecting the oil level, do not screw
the dipstick into the oil tank. Insert the gauge
lightly.
(For USA and CDN)
CAUTION:
 Do not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
 Do not allow foreign material to enter the
crankcase.
(Except for USA and CDN)
CAUTION:
 Do not add any chemical additives or use
oils with a grade of CD a or higher.
 Do not use oils labeled “ENERGY CON-
SERVING II ” b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
 Do not allow foreign materials to enter the
crankcase.
Recommended oil:
At –10 °C (14 °F) or higher È:
Yamalube 4 (10W-30) or SAE
10W-30 type SE/SF/SG motor
oil
At 5 °C (41 °F) or higher É:
Yamalube 4 (20W-40) or SAE
20W-40 type SE/SF/SG motor
oil
Recommended oil: Refer to the following chart for
selection of oils which are suited
to the atmospheric temperatures.
Recommended engine oil classifi-
cation:
API STANDARD: API “SE/SF/SG ” or higher grade
(Designed primarily for
motorcycles)
0 10 30 50 70
90110
130
-20 -10 010
20 30 40 50
È
É
˚C
˚
F
a
b
ENGINE OIL LEVEL INSPECTION

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INSPADJIDLE SPEED ADJUSTMENT/
VALVE CLEARANCE ADJUSTMENT
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Attach:
Tachometer
To spark plug lead.
3. Adjust:
Idle speed
Adjustment steps:
Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed → Turn the throt-
tle stop screw 1 in
a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out
b.
Engine idling speed:
1,600 ~ 1,800 r/min
1
a
b
VALVE CLEARANCE ADJUSTMENT
NOTE:
 The valve clearance should be adjusted
when the engine is cool to the touch.
 The piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove: Spark plug cap 1
 Spark plug
 Tappet cover (intake side) 2
 Tappet cover (exhaust side) 3
 Camshaft sprocket cover 4
3
4
1
2
2. Remove:
Timing plug 1
 Crankshaft end cover 2
 O-rings
1
2

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INSPADJ
6. Lubricate:
Drive chain
Drive chain lubricant:
SAE 10W-30 motor oil or
suitable chain lubricants
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check: Drive chain slack a
In the center between the drive axle and
rear wheel axle.
Out of specification → Adjust.
NOTE:
Before checking and/or adjusting, rotate the
rear wheel through several revolutions and
check the slack several times to find the tight-
est point. Check and/or adjust chain slack with
rear wheel in this “tight chain ” position.
Drive chain slack:
35 ~ 45 mm (1.38 ~ 1.77 in)
3. Adjust:
Drive chain slack
Drive chain slack adjustment steps:
 Loosen the wheel axle nut 1 and locknuts
2 .
 Adjust chain slack by turning the adjusters
3 .
To tighten → Turn adjuster 3 clockwise a.
To loosen → Turn adjuster 3 counter-
clockwise b and push wheel forward.
 Turn each adjuster exactly the same
amount to maintain correct axle alignment.
(There are marks c on each side of chain
puller alignment.)
1 b
c
a
23
DRIVE CHAIN INSPECTION/
DRIVE CHAIN SLACK ADJUSTMENT

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INSPADJWHEEL INSPECTION/
STEERING HEAD INSPECTION AND ADJUSTMENT
2. Inspect:
Bearing free play
Exist play → Replace.
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Check:
Steering head
Grasp the bottom of the forks and gently
rock the fork assembly back and forth.
Free play → Adjust the steering head.
3. Check: Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action → Adjust the steering
head.
4. Adjust:
Steering head
Steering ring nut adjustment steps:
 Remove the front fender 1.
 Remove the handlebar 2, upper bracket
bolts 3, steering stem nut 4 and upper
bracket 5.
1
4
3
52

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INSPADJ
ELECTRICAL/SPARK PLUG INSPECTION
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:
Spark plug
2. Inspect: Electrode 1
Wear/damage → Replace.
 Insulator color 2
Normal condition is a medium to light tan
color.
Distinctly different color → Check the
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure: Plug gap a
Use a wire gauge or thickness gauge.
Out of specification → Regap.
4. Clean the plug with a spark plug cleaner if necessary.
5. Tighten: Spark plug
NOTE:
 Before installing a spark plug, clean the gas-
ket surface and plug surface.
 Finger-tighten a the spark plug before torqu-
ing to specification b.
Spark plug gap:
0.6 ~ 0.7 mm (0.024 ~ 0.028 in)
Standard spark plug: CR7HSA (NGK)
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)

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ENGSHIFT FORK, SHIFT CAM AND TRANSMISSION
2. Install:Main axle assembly 1
 Drive axle assembly 2
 Shift fork 2 “R ” 3
 Shift fork 1 “L ” 4
 Shift cam 5
 Guide bar 6
NOTE:
The embossed marks on the shift forks
should face towards the right side of the
engine and be in the following sequence:
“R ”, “L ”.
 Mesh the shift fork 2 “R ” with the 3rd wheel
gear on the drive axle.
 Mesh the shift fork 1 “L ” with the 2nd pinion
gear on the main axle.
3. Check: Shifter operation
 Transmission operation
Unsmooth operation → Repair.
3
4
5 1
6
2

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CHAS
3. Install:Engine stop switch 1
NOTE:
Align the tab a on the engine stop switch
holder with the hole b in the handlebar.
a
b
1
4. Install:
Start switch 1
NOTE:
Align the mating surfaces a of the start switch
with the punch mark b on the handlebar.
1
b a
5. Install:
Throttle cable 1
NOTE:
After installing the throttle cable, insert the rub-
ber seal and throttle cable guide completely
into the hole in the start switch housing, mak-
ing sure that the rubber seal flange a, throttle
cable guide flange b, and housing c contact
each other.
a
c b
1
6. Install:
Screws (start switch) 1
WARNING
After tightening the screws, check that the
throttle grip 2 moves smoothly. If it does
not, retighten the screws for adjustment.
2
1
HANDLEBAR

–+ELEC
6 - 2
IGNITION SYSTEM
EC620000
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to
ignition system failure and for checking the spark plug which will not spark.
NOTE:
Remove the following parts before inspection.
1) Seat assembly
2) Air scoops (left and right)
3) Fuel tank
Refer to “FRONT FENDER, SEAT ASSEMBLY AND FUEL TANK ” section in the CHAPTER 4.
 Use the following special tools in this inspection.
Opama pet-4000 spark checker:
YM-34487
Ignition checker: 90890-06754Pocket tester:YU-03112-C/90890-03112
Spark gap test Clean or replace
spark plug.
Check entire ignition
system for connection. Repair or replace.
Check main switch. Replace.
Check engine stop switch. Replace.
Check ignition coil. Primary coil Replace. Secondary coil Replace.
Check AC magneto. Pickup coil Replace. Replace CDI unit.
No Spark
OK
OK
OK
OK
OK
Spark
No good
No good
No good
No good
No good
No good