2021 YAMAHA YFZ50 transmission

EBU17421
TABLE OF CONTENTS
VEHICLE IDENTIFICATION ............................ 1-1Identification numbers ................................ 1-1
LOCATION OF THE WARNING AND
SPECIFICATION LABELS .............................. 2-1
SAFETY INFORMATION ................................ 3-1
DESCRIPTION................................................ 4-1 Left view ...................................................... 4-1
Right view.................................................... 4-1
Controls and instruments............................ 4-2
INSTRUMENT AND CONTROL
FUNCTIONS ................................................... 5-1 Main switch ................................................. 5-1
Handlebar switches .................................... 5-1
Engine stop switch with lanyard ................. 5-2
Throttle lever ............................................... 5-3
Speed limiter ............................................... 5-3
Front brake lever ......................................... 5-5
Rear brake lever .......................................... 5-6
Parking brake .............................................. 5-6
Kickstarter ................................................... 5-7 Fuel tank cap .............................................. 5-8
Fuel ............................................................. 5-9
Fuel cock .................................................. 5-10
Starter (choke) ......................................... 5-12
Seat .......................................................... 5-13
Rear shock absorber ................................ 5-13
PRE-OPERATION CHECKS .......................... 6-1 Fuel ............................................................. 6-3
Engine oil .................................................... 6-3
Transmission oil .......................................... 6-3
Front and rear brakes ................................. 6-3
Throttle lever ............................................... 6-3
Drive chain .................................................. 6-3
Tires ............................................................ 6-3
Chassis fasteners ....................................... 6-6
Instruments and switches........................... 6-6
OPERATION .................................................. 7-1 Starting a cold engine................................. 7-1
Starting a warm engine............................... 7-3
Engine break-in........................................... 7-3
Parking........................................................ 7-3
Parking on a slope ...................................... 7-4UBW464E0.book Page 1 Thursday, January 23, 2020 2:42 PM

Accessories and loading ............................. 7-5
RIDING YOUR ATV ........................................ 8-1 GETTING TO KNOW YOUR ATV ................ 8-2
RIDE WITH CARE AND GOOD JUDGMENT .............................................. 8-2
BE CAREFUL WHERE YOU RIDE ............... 8-9
TURNING YOUR ATV................................ 8-12
CLIMBING UPHILL ................................... 8-13
RIDING DOWNHILL .................................. 8-16
CROSSING A SLOPE................................ 8-17
CROSSING THROUGH SHALLOW WATER .................................................... 8-18
RIDING OVER ROUGH TERRAIN ............. 8-20
SLIDING AND SKIDDING .......................... 8-20
WHAT TO DO IF... ..................................... 8-21
PERIODIC MAINTENANCE AND
ADJUSTMENT................................................ 9-1 Owner’s Manual and tool kit ....................... 9-2
Periodic maintenance chart: Emission control system .......................................... 9-3
Periodic maintenance chart: General maintenance and lubrication..................... 9-5
Removing and installing the panel .............. 9-9
Checking the spark plug ............................. 9-9
Engine oil................................................... 9-11 Why Yamalube.......................................... 9-14
Transmission oil ........................................ 9-15
Cleaning the air filter element ................... 9-16
Cleaning the spark arrester ...................... 9-19
Adjusting the carburetor ........................... 9-20
Adjusting the engine idling speed ............ 9-20
Adjusting the throttle lever free play ......... 9-22
Valve clearance......................................... 9-22
Brakes....................................................... 9-22
Checking the front and rear brake
shoes ...................................................... 9-23
Adjusting the front brake lever free play... 9-24
Adjusting the rear brake lever free play .... 9-26
Drive chain slack....................................... 9-26
Cleaning and lubricating the drive chain ....................................................... 9-29
Checking and lubricating the cables ........ 9-29
Checking and lubricating the front and rear brake levers ..................................... 9-30
Checking the wheel hub bearings ............ 9-30
Lubricating the front arm pivots ............... 9-31
Lubricating the front knuckle pivots ......... 9-31
Lubricating the steering shaft ................... 9-32
Battery ...................................................... 9-32
Replacing the fuse .................................... 9-35
Removing a wheel .................................... 9-36
Installing a wheel ...................................... 9-36
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4-1
4
EBU17681
DESCRIPTION
EBU17691Left view
EBU17701Right view
1. Fuel tank cap
2. Fuel cock
3. Air filter
4. Engine stop switch with cord (lanyard)
5. Rear shock absorber
6. Kickstarter lever cap
7. Throttle stop screw
12
4
5
3
6
7
1. Spark arrester
2. Reflector
3. Tool kit
4. Fuse
5. Battery
6. Spark plug
7. Engine oil filler cap
8. Transmission oil filler cap1
23
4,5
6
78
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6-1
6
EBU19203
PRE-OPERATION CHECKS
EBU19227Inspect your vehicle each time you use it to make sure the vehicle is in safe operating condition. Always
follow the inspection and maintenance procedures and schedules described in the Owner’s Manual.
WARNING
EWB00482Failure to inspect or maintain the vehicle properly increases the possibility of an accident or equip-
ment damage. Do not operate the vehicle if you find any problem. If a problem cannot be corrected
by the procedures provided in this manual, have the vehicle inspected by a Yamaha dealer. Before using this vehicle, check the following points:
ITEMROUTINE PAGE
Fuel • Check fuel level in fuel tank,
and add recommended fuel if neces-
sary.
• Check fuel line for leakage. Correct if necessary. 5-9, 6-3
Engine oil • Check oil level in engine, and add recommended oil to specified
level if necessary.
• Check ATV for oil leakage. Correct if necessary. 6-3, 9-11
Transmission oil • Check ATV for oil leakage. Correct if necessary. 6-3, 9-15
Front brake • Check operation, and correct if necessary.
• Lubricate cable if necessary.
• Check lever free play, and adjust if necessary. 6-3, 9-23, 9-24
Rear brake • Check operation, and correct if necessary.
• Lubricate cable if necessary.
• Check lever free play, and adjust if necessary. 6-3, 9-23, 9-26
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6-3
6
EBU38000FuelMake sure there is sufficient gasoline in the tank
before starting off. Refuel if necessary. (See page
5-9.)EBU19561Engine oilMake sure that the engine oil is at the specified
level. Add oil as necessary. (See page 9-11.)EBU34490Transmission oilMake sure that the transmission oil is at the spec-
ified level. Add oil as necessary. (See page 9-15.)EBU19653Front and rear brakesBrake levers
Check for correct free play in the brake levers. If
the free play is incorrect, adjust it. (See pages
9-24 and 9-26.)
 Check operation of the levers. They should
move smoothly and there should be a firm feel-
ing when the brake is applied. If not, have the
ATV checked by a Yamaha dealer. Brake operation
Test the brakes at slow speed after starting out to
make sure they are working properly. If the brakes
do not provide proper braking performance,
check the brake shoes for wear. (See page 9-23.)
EBU19762Throttle leverCheck the operation of the throttle lever. It must
open smoothly and spring back to the idle position
when released. Have a Yamaha dealer correct if
necessary.EBU19771Drive chainCheck the condition of the drive chain and check
the drive chain slack. Lubricate and adjust the
drive chain as necessary. (See page 9-26.)EBU1979ATiresCheck tire pressure regularly to make sure it is at
the recommended specifications. Also check for
wear and damage.
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9-7
9
15*Steering system • Check operation and repair or replace if dam-
aged.
• Check toe-in and adjust if necessary. √√√√√
16 Engine oil • Change.
• Check ATV for oil leakage, and correct if neces-
sary. √ √√√
17 Engine oil strainer • Clean. √√√
18 Transmission oil • Change.
• Check ATV for oil leakage, and correct if neces-
sary. √√
19 *Moving parts and
cables
• Lubricate.
√√√√
20 *Throttle lever • Check operation.
• Check throttle lever free play, and adjust if neces-
sary.
• Lubricate cable and lever housing. √√√√√
21 *Brake switch • Check operation and correct if necessary. √√√√√
22 *Switches • Check operation and correct if necessary. √√√√√
NO. ITEM
CHECK OR MAINTENANCE
JOB INITIAL EVERY
Whichev-
er comes first month136612
km (mi) 240
(150) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320UBW464E0.book Page 7 Thursday, January 23, 2020 2:42 PM

9-15
9
EBU34473Transmission oilThe transmission case must be checked for oil
leakage before each ride. If any leakage is found,
have a Yamaha dealer check and repair the ATV.
In addition, the transmission oil must be changed
at the intervals specified in the periodic mainte-
nance chart.
To change the transmission oil1. Place the ATV on a level surface.
2. Place an oil pan under the transmission case to collect the used oil.
3. Remove the transmission oil filler cap and its O-ring from the transmission case. 4. Remove the transmission oil drain bolt and its
gasket to drain the oil from the transmission
case.
1. Transmission oil filler cap
2. O-ring12
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9-16
9
5. Install the transmission oil drain bolt and its
new gasket, and then tighten the bolt to the
specified torque.
6. Refill with the specified amount of the recom- mended oil. NOTICE: Make sure that no
foreign material enters the transmission
case.
[ECB03380]
7. Check the oil filler cap O-ring for damage, and replace it if necessary.
8. Install and tighten the oil filler cap.
9. Check the transmission case for oil leakage. If oil is leaking, check for the cause.EBU34111Cleaning the air filter elementThe air filter element should be serviced at the in-
tervals specified in the periodic maintenance
chart. Clean or, if necessary, replace the air filter
element more frequently if you are riding in unusu-
ally wet or dusty areas.TIPThere is a check hose at the bottom of the air filter
case. If dust or water collects in this hose, empty
the hose and clean the air filter element and air fil-
ter case.
1. Transmission oil drain bolt
2. GasketTightening torque:Transmission oil drain bolt:30 N