2020 YAMAHA YZ85 engine

Periodic maintenance an d a djustment
7-32
7
EAU86410
Trou bleshootin g chart
1. FuelThere is enough fuel.
There is no fuel.
Check the ignition.
Supply fuel.The engine does not
start.
Check the ignition.
Open the throttle
halfway and try
starting the engine.
Wipe off with a dry
cloth and correct the
spark plug gap, or
replace the spark
plug(s).
2. IgnitionWet
Dry
There is compression.
There is no
compression.
The engine does not start.
Have a Yamaha dealer check the vehicle.
Have a Yamaha dealer check the vehicle.
The engine does not
start.
Check the
compression.Have a Yamaha
dealer check the
vehicle.
Remove the spark
plug and check
the electrodes.
Try starting the
engine.
Check the fuel level
in the fuel tank.
3. Compression
UB4B81E0.book Page 32 Friday, March 1, 2019 2:54 PM

Periodic maintenance an d a djustment
7-33
7
EAU86430En gine overheatin g
WARNING
EWAT1041
Do not remove the rad iator cap when the engine an d ra diator are hot.
Scal din g hot flui d an d steam may b e blown out un der pressure, which
coul d cause serious injury. Be sure to wait until the en gine has coole d.
 Place a thick ra g, like a towel, over the rad iator cap, and then slowly ro-
tate the cap counterclockwise to the d etent to allow any residual pres-
sure to escape. When the hissin g soun d has stoppe d, press d own on the
cap while turnin g it counterclockwise, an d then remove the cap.
TIP
If coolant is not available, tap water can be temporarily used instead, provided
that it is changed to the recommended coolant as soon as possible.
Wait until the engine
has cooled.
Check the coolant
level in the reservoir
and radiator.Add coolant.
(See TIP.)
The coolant level is
OK.
There is no leakage.
There is leakage.
The coolant level is
low.
Check the cooling
system for leakage.
Have a Yamaha
dealer check and
repair the cooling
system.
Start the engine. If the engine overheats again,
have a Yamaha dealer check and repair the cooling
system.
UB4B81E0.book Page 33 Friday, March 1, 2019 2:54 PM

Motorcycle care and stora ge
8-3
8 2. For drive chain-equipped models:
Dry and then lubricate the drive
chain to prevent rust.
3. Use a chrome polish to shine chrome, aluminum, and stainless
steel parts. Often the thermally in-
duced discoloring of stainless
steel exhaust systems can be re-
moved through polishing.
4. Apply a corrosion protection spray on all metal parts including
chrome or nickel-plated surfaces.
WARNING! Do not apply silicone or oil spray to seats, han d g rips,
ru bber foot pe gs or tire trea ds.
Otherwise these parts will be-
come slippery, which coul d
cause loss of control. Thor-
ou ghly clean the surfaces of
these parts before operatin g the
vehicle.
[EWA20650]
5. Treat rubber, vinyl, and unpainted plastic parts with a suitable care
product.
6. Touch up minor paint damage caused by stones, etc.
7. Wax all painted surfaces using a non-abrasive wax or use a detail
spray for motorcycles.
8. When finished cleaning, start the engine and let it idle for several mi-
nutes to help dry any remaining
moisture.
9. If the headlight lens has fogged up, start the engine and turn on
the headlight to help remove the
moisture.
10. Let the vehicle dry completely be- fore storing or covering it.
NOTICE
ECA26320
Do not apply wax to ru bber or
unpainte d plastic parts.
 Do not use a brasive polishin g
compoun ds as they will wear
away the paint.
 Apply sprays an d wax sparin gly.
Wipe off excess afterwar ds.
WARNING
EWA20660
Contaminants left on the b rakes or
tires can cause loss of control.  Make sure there is no lu bricant
or wax on the brakes or tires.
 If necessary, wash the tires with
warm water an d a mil d d eter-
g ent.
 If necessary, clean the brake
d iscs an d pa ds with b rake
cleaner or acetone.
 Before ri din g at hi gher spee ds,
test the vehicle’s brakin g per-
formance an d cornerin g b ehav-
ior.
UB4B81E0.book Page 3 Friday, March 1, 2019 2:54 PM

Motorcycle care and stora ge
8-4
8
EAU86460
Stora ge
Always store the vehicle in a cool, dry
place. If necessary, protect it against
dust with a porous cover. Be sure the
engine and the exhaust system are
cool before covering the vehicle. If the
vehicle often sits for weeks at a time
between uses, the use of a quality fuel
stabilizer is recommended after each
fill-up.
NOTICE
ECA21170
 Storin g the vehicle in a poorly
ventilate d room or coverin g it
with a tarp, while it is still wet,
will allow water an d humi dity to
seep in an d cause rust.
 To prevent corrosion, avoi d
d amp cellars, sta bles ( because
of the presence of ammonia)
an d areas where stron g chemi-
cals are store d.
Lon g term stora ge
Before storing the vehicle long term (60
days or more): 1. Make all necessary repairs and perform any outstanding mainte-
nance.
2. Follow all instructions in the Care Section of this chapter.
3. Fill up the fuel tank and add fuel stabilizer according to product in-
structions.
4. Run the engine for 5 minutes to distribute treated fuel through the
fuel system.
5. For vehicles with a fuel cock: Turn the fuel cock lever to the off posi-
tion. 6. For vehicles with a carburetor: To
prevent fuel deposits from build-
ing up, drain the fuel in the carbu-
retor float chamber into a clean
container. Retighten the drain bolt
and pour the fuel back into the fuel
tank.
7. Use a quality engine fogging oil according to product instructions.
If engine fogging oil is not avail-
able, perform the following steps
for each cylinder:a. Remove the spark plug cap and spark plug.
b. Pour a teaspoonful of engine oil into the spark plug bore.
c. Install the spark plug cap onto the spark plug, and then place
the spark plug on the cylinder
head so that the electrodes are
grounded. (This will limit spark-
ing during the next step.)
d. Turn the engine over several times with the starter or kick-
starter. (This will coat the cylin-
der wall with oil.) WARNING!
To prevent d amage or injury
from sparkin g, make sure to
g roun d the spark plu g elec-
tro des while turnin g the en-
g ine over.
[EWA10952]
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap.
8. Lubricate all control cables, piv- ots, levers and pedals, as well as
the sidestand and centerstand (if
equipped).
9. Check and correct the tire air pressure, and then lift the vehicle
so that all wheels are off the
UB4B81E0.book Page 4 Friday, March 1, 2019 2:54 PM

Specifications
9-1
9
Dimensions:
Overall length:1820 mm (71.7 in) (YZ85, YZ85L)
1895 mm (74.6 in) (YZ85LW, YZ85LWL)
Overall width: 760 mm (29.9 in)
Overall height:
1145 mm (45.1 in) (YZ85, YZ85L)
1175 mm (46.3 in) (YZ85LW, YZ85LWL)
Seat height:
840 mm (33.1 in) (YZ85, YZ85L)
870 mm (34.3 in) (YZ85LW, YZ85LWL)
Wheelbase:
1255 mm (49.4 in) (YZ85, YZ85L)
1285 mm (50.6 in) (YZ85LW, YZ85LWL)
Ground clearance: 330 mm (12.99 in) (YZ85, YZ85L)
360 mm (14.17 in) (YZ85LW, YZ85LWL)
Wei ght:
Curb weight:
73 kg (161 lb) (YZ85, YZ85L)
75 kg (165 lb) (YZ85LW, YZ85LWL)
Engine:
Combustion cycle:
2-stroke
Cooling system: Liquid cooled
Number of cylinders:
Single cylinder
Displacement: 85 cm³
Bore × stroke:
47.5 × 47.8 mm (1.87 × 1.88 in)
Starting system:
Kickstarter
Engine oil:
Engine oil:
YAMALUBE 2R
Recommended brand:
Transmission oil:
Type:
Motor oil SAE 10W-30 type SE or higher or
Gear oil SAE 85W GL-3
Quantity:
0.50 L (0.53 US qt, 0.44 Imp.qt)
Coolant quantity:
Radiator (including all routes): 0.55 L (0.58 US qt, 0.48 Imp.qt)
Fuel:
Recommended fuel:Unleaded gasoline (E10 acceptable)
Octane number (RON): 98
Fuel tank capacity:
5.0 L (1.3 US gal, 1.1 Imp.gal)
Car buretor:
Type × quantity:
PWK28 × 1
Drivetrain:
Gear ratio:
1st:
2.455 (27/11)
2nd:
1.882 (32/17)
3rd: 1.529 (26/17)
4th: 1.294 (22/17)
5th:
1.130 (26/23)
6th: 1.000 (25/25)
Front tire:
Type:
With tube
Size: 70/100-17 40M (YZ85, YZ85L)
70/100-19 42M (YZ85LW, YZ85LWL)
Manufacturer/model: DUNLOP/MX3SF
Rear tire:
Type:
With tube
Size: 90/100-14 49M (YZ85, YZ85L)
90/100-16 52M (YZ85LW, YZ85LWL)
Manufacturer/model: DUNLOP/MX3S
Front brake:
Type:
Hydraulic single disc brake
Rear brake:
Type:
Hydraulic single disc brake
UB4B81E0.book Page 1 Friday, March 1, 2019 2:54 PM

Consumer information
10-1
10
EAU26366
Id entification num bers
Record the vehicle identification num-
ber and the engine serial number in the
spaces provided below for assistance
when ordering spare parts from a
Yamaha dealer or for reference in case the vehicle is stolen.
VEHICLE IDENTIFICATION NUMBER:
ENGINE SERIAL NUMBER:
EAU26401Vehicle i dentification num ber
The vehicle identification number is
stamped into the steering head pipe.
Record this number in the space pro-
vided.
TIP
The vehicle identification number is
used to identify your motorcycle and
may be used to register your motorcy-
cle with the licensing authority in your
area.
EAU26442En gine serial num ber
The engine serial number is stamped
into the crankcase.
1. Vehicle identification number
1. Engine serial number
1
UB4B81E0.book Page 1 Friday, March 1, 2019 2:54 PM

11-1
11
Index
A
Air filter element, cleaning .................... 7-10
B
Brake and clutch levers, checking and
lubricating ........................................... 7-24
Brake fluid, changing ............................ 7-21
Brake fluid level, checking .................... 7-20
Brake lever .............................................. 4-2
Brake lever free play, checking............. 7-18
Brake pedal............................................. 4-3
Brake pedal, checking and lubricating ........................................... 7-25
C
Cables, checking and lubricating ......... 7-23
Carburetor, adjusting ............................ 7-12
Care ........................................................ 8-1
Clutch lever ............................................. 4-1
Clutch lever free play, adjusting ........... 7-17
Coolant ................................................... 7-8
D
Drive chain, cleaning and lubricating .... 7-23
Drive chain slack................................... 7-21
E
Engine break-in....................................... 6-1
Engine idling speed .............................. 7-13
Engine overheating ............................... 7-33
Engine serial number ............................ 10-1
Engine, starting a warm .......................... 6-3
Engine stop switch ................................. 4-1
F
Front and rear brake pads, checking.... 7-19
Front fork, adjusting................................ 4-9
Front fork, bleeding .............................. 4-11
Front fork, checking .............................. 7-26
Fuel ......................................................... 4-4
Fuel cock ................................................ 4-7
Fuel tank breather hose .......................... 4-6
Fuel tank cap .......................................... 4-3
H
Handlebar switch .................................... 4-1
I
Identification numbers .......................... 10-1
K
Kickstarter............................................... 4-8
L
Labels, location....................................... 1-1
M
Matte color, caution ................................ 8-1
P
Parking .................................................... 6-5 Part locations ......................................... 3-1
Periodic maintenance and lubrication
chart ..................................................... 7-2
R
Rear suspension, lubricating ................ 7-25
S
Safety information .................................. 2-1
Seat ........................................................ 4-8
Shifting ................................................... 6-4
Shift pedal .............................................. 4-2
Shift pedal, checking ............................ 7-18
Shock absorber assembly, adjusting ... 4-12
Sidestand ............................................. 4-15
Spark plug, checking ............................. 7-6
Specifications ......................................... 9-1
Starter (choke) knob ............................... 4-7
Starting and warming up a cold engine .................................................. 6-3
Steering, checking................................ 7-27
Storage ................................................... 8-4
Supporting the motorcycle................... 7-28
Swingarm pivots, lubricating ................ 7-26
T
Throttle grip and cable, checking and lubricating .......................................... 7-24
Throttle grip free play, adjusting........... 7-13
Tires ...................................................... 7-14
Transmission oil ..................................... 7-7
Troubleshooting ................................... 7-31
Troubleshooting chart .......................... 7-32
V
Vehicle identification number ............... 10-1
W
Wheel bearings, checking .................... 7-27
Wheel (front) ......................................... 7-28
Wheel (rear) .......................................... 7-29
Wheels .................................................. 7-16
Y
YPVS system ........................................ 4-16
UB4B81E0.book Page 1 Friday, March 1, 2019 2:54 PM