Page 23 of 86
DESCRIPTION
3-1
3
EAU10410
Left view1. Radiator cap (page 7-10)
2. Fuel cock (page 4-5)
3. Shock absorber assembly spring preload adjusting nut (page 4-9)
4. Air filter element (page 7-12)
5. Seat (page 4-7)
6. Shift pedal (page 4-1)
7. Throttle stop screw (page 7-14)
8. Starter (choke) knob (page 4-6)
U5PA89E0.book Page 1 Tuesday, June 15, 2010 10:34 AM
Page 48 of 86
PERIODIC MAINTENANCE AND ADJUSTMENT
7-4
7
NO. ITEM ROUTINEAfter
break-inEvery
raceEvery
third raceEvery
fifth raceAs
required
√
√
√ 13*CarburetorCheck carburetor settings and for obstructions.√
Adjust and clean.√
14 Spark plugCheck condition.
Clean and regap.√
Replace.√
15 Drive chainCheck chain slack, alignment and condition.
Adjust and thoroughly lubricate chain with Yamaha
chain and cable lube or equivalent.√
√
√
√ √
Replace.√
16* *
Cooling systemCheck coolant level and for leakage.√ √
Check hoses for cracks or damage.√
Check radiator cap spring operation.√
Change coolant. Every 2 years√
17*Chassis fastenersCheck all chassis fitting and fasteners.
Correct or tighten if necessary.√
18*Air filter elementClean.
√
Replace.√
19*FrameClean and check for damage.√
20*Fuel line Clean and check for leakage.√√
U5PA89E0.book Page 4 Tuesday, June 15, 2010 10:34 AM
Page 54 of 86

PERIODIC MAINTENANCE AND ADJUSTMENT
7-10
7
NOTICE
ECA10452
In order to prevent clutch slip-
page (since the transmission 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 CONSERVING II” or
higher.
Make sure that no foreign mate-
rial enters the transmission.
7. 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.
EAU20070
Coolant The coolant level should be checked
before each ride. In addition, the cool-
ant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUM1294
To check the coolant level
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.
2. Remove the radiator cap and
check the coolant level in the radi-
ator. WARNING! Never attempt
to remove the radiator cap when
the engine is hot.
[EWA10381]
TIP
The coolant level must be checked
on a cold engine since the level
varies with engine temperature.
Make sure that the vehicle is posi-
tioned straight up when checking
the coolant level. A slight tilt to the
side can result in a false reading.
TIPThe coolant should be at the bottom of
the radiator filler neck. The level will
change with variation of engine temper-
ature.3. If the coolant is below this level,
add coolant, and then install the
radiator cap. NOTICE: If coolant
1. Radiator cap
1. Correct coolant level
U5PA89E0.book Page 10 Tuesday, June 15, 2010 10:34 AM
Page 55 of 86

PERIODIC MAINTENANCE AND ADJUSTMENT
7-11
7 is not available, use distilled wa-
ter or soft tap water instead. Do
not use hard water or salt water
since it is harmful to the engine.
If water has been used instead
of coolant, replace it with cool-
ant as soon as possible, other-
wise the cooling system will not
be protected against frost and
corrosion. If water has been
added to the coolant, have a
Yamaha dealer check the anti-
freeze content of the coolant as
soon as possible, otherwise the
effectiveness of the coolant will
be reduced.
[ECA10472]
EAUM1315
To change the coolant
1. Place the vehicle on a level sur-
face and let the engine cool if nec-
essary.
2. Place a container under the engine
to collect the used coolant.
3. Remove the coolant drain bolt and
its gasket, and then the radiator
cap to drain the cooling system.WARNING! Never attempt to re-
move the radiator cap when the
engine is hot.
[EWA10381]
4. After the coolant is completely
drained, thoroughly flush the cool-
ing system with clean tap water.5. Install the coolant drain bolt and its
new gasket, and then tighten the
bolt to the specified torque.
6. Pour the recommended coolant
into the radiator until it is full.
7. Install the radiator cap, start the
engine, let it idle for several min-
utes, and then turn it off.
8. Remove the radiator cap to check
the coolant level in the radiator. If
necessary, add sufficient coolant
until it reaches the bottom of the
radiator filler neck, and then install
the radiator cap.1. Coolant drain bolt
2. Gasket
1. Radiator cap
1
1
2
Tightening torque:
Coolant drain bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Antifreeze/water mixture ratio:
1:1
Recommended antifreeze:
High-quality ethylene glycol anti-
freeze containing corrosion inhibi-
tors for aluminum engines
Coolant quantity:
Radiator capacity (including all
routes):
0.54 L (0.57 US qt, 0.48 Imp.qt)
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-32
7Engine overheating
WARNING
EWAT1040
Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.
Place a thick rag, like a towel, over the radiator cap, and then slowly rotate the cap counterclockwise to the de-
tent to allow any residual pressure to escape. When the hissing sound has stopped, press down on the cap
while turning it counterclockwise, and then remove the cap.
TIPIf 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
radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again,
have a
Yamaha dealer check
and repair the cooling system.
There is
leakage.
There is
no leakage.
U5PA89E0.book Page 32 Tuesday, June 15, 2010 10:34 AM
Page 81 of 86

SPECIFICATIONS
9-1
9
Dimensions:Overall length:
YZ85 1818 mm (71.6 in)
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85 1821 mm (71.7 in) (ZAF)
YZ85A 1818 mm (71.6 in)
YZ85LW 1903 mm (74.9 in)
YZ85LWA 1903 mm (74.9 in)
Overall width:
758 mm (29.8 in)
Overall height:
YZ85 1161 mm (45.7 in)
YZ85A 1161 mm (45.7 in)
YZ85LW 1205 mm (47.4 in)
YZ85LWA 1205 mm (47.4 in)
Seat height:
YZ85 864 mm (34.0 in)
YZ85A 864 mm (34.0 in)
YZ85LW 904 mm (35.6 in)
YZ85LWA 904 mm (35.6 in)
Wheelbase:
YZ85 1255 mm (49.4 in)
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85 1258 mm (49.5 in) (ZAF)
YZ85A 1255 mm (49.4 in)
YZ85LW 1286 mm (50.6 in)
YZ85LWA 1286 mm (50.6 in)Ground clearance:
YZ85 351 mm (13.82 in)
YZ85A 351 mm (13.82 in)
YZ85LW 393 mm (15.47 in)
YZ85LWA 393 mm (15.47 in)
Weight:Curb weight:
YZ85 71 kg (157 lb)
YZ85A 71 kg (157 lb)
YZ85LW 73 kg (161 lb)
YZ85LWA 73 kg (161 lb)Engine:Engine type:
Liquid cooled 2-stroke
Cylinder arrangement:
Single cylinder
Displacement:
84 cm³
Bore × stroke:
47.5 × 47.8 mm (1.87 × 1.88 in)
Compression ratio:
8.20 :1
Starting system:
Kickstarter
Lubrication system:
PremixEngine oil:Type:
YAMALUBE 2RTransmission oil:Type:
YAMALUBE 4 (10W-40) or SAE 10W-40
Oil change quantity:
0.50 L (0.53 US qt, 0.44 Imp.qt)
Cooling system:Radiator capacity (including all routes):
0.54 L (0.57 US qt, 0.48 Imp.qt)Air filter:Air filter element:
Wet elementFuel:Recommended fuel:
Premium unleaded gasoline only
Fuel tank capacity:
5.0 L (1.32 US gal, 1.10 Imp.gal)Carburetor:Type × quantity:
PWK28 x 1Spark plug(s):Manufacturer/model:
NGK/BR10EG
Spark plug gap:
0.5–0.6 mm (0.020–0.024 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction ratio:
65/18 (3.611)
Final drive:
Chain
U5PA89E0.book Page 1 Tuesday, June 15, 2010 10:34 AM