2004 YAMAHA YZ85 fuel cap

GEN
INFO
1 - 1
DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1Clutch lever
2Engine stop switch
3Front brake lever
4Throttle grip
5Fuel tank cap
6Radiator cap
7Kickstarter crank
8Fuel tank
9Coolant drain bolt
0Rear brake pedal
ARadiator
BValve joint
CFuel cock
DAir filter
EDrive chain
FShift pedal
GStarter knob
HFront forkNOTE:

The machine you have purchased may differ
slightly from those shown in the following.

Designs and specifications are subject to
change without notice.
5PA10020
5PA10010
5PAR0001

1 - 12
GEN
INFO
FUEL AND ENGINE MIXING OIL
FUEL AND ENGINE MIXING OIL
Mix oil with the gas at the ratio specified below.
Always use fresh, name-brand gasoline, and
mix the oil and gas the day of the race. Do not
use premix that is more than a few hours old.
NOTE:
If knocking or pinging occurs, use a different
brand of gasoline or higher octane grade.
CAUTION:
Never mix two types of oil in the same
batch; clotting of the oil could result. If you
wish to change oil types, be sure to drain
the fuel tank and the carburetor float bowl
of old premix prior to filling with the new
type.
Recommended fuel:
Except for ZA:
Premium unleaded gasoline
only with a research octane
number of 95 or higher.
For ZA:
Premium gasoline
Fuel tank capacity:
5 L (1.10 Imp gal, 1.32 US gal)
Mixing oil
Recommended oil:
Yamalube “2-R”
(Yamalube racing 2-cycle oil)
Mixing ratio: 30 : 1
If unavailable, use an equivalent
type of oil.
5PA10540

SPEC
2 - 1
GENERAL SPECIFICATIONS
EC200000
SPECIFICATIONS
EC211000
GENERAL SPECIFICATIONS
Model name: YZ85 YZ85LW
YZ85S (USA)
YZ85LC (EUROPE)
YZ85(S)
(CDN, AUS, NZ, ZA)YZ85LW (EUROPE)
YZ85LWS (AUS, NZ)
Model code number: YZ85 YZ85LW
5PA7
(USA, CDN, EUROPE,
NZ, ZA)
5PA8
(AUS)5SH7
(EUROPE, NZ)
5SH8
(AUS)
Dimensions: YZ85 YZ85LW
Overall length 1,821 mm (71.7 in) 1,903 mm (74.9 in)
(USA, S, NZ, ZA)
1,818 mm (71.6 in)
(F, D, I, GB, E, CDN,
AUS)
Overall width 758 mm (28.9 in)←
Overall height 1,161 mm (45.7 in) 1,205 mm (47.4 in)
Seat height 864 mm (34.0 in) 904 mm (35.6 in)
Wheelbase 1,258 mm (49.5 in) 1,286 mm (50.6 in)
(USA, S, NZ, ZA)
1,255 mm (49.4 in)
(F, D, I, GB, E, CDN,
AUS)
Minimum ground clearance 351 mm (13.8 in) 393 mm (15.5 in)
Basic weight: YZ85 YZ85LW
With oil and full fuel tank 71 kg (156.5 lb) 73.9 kg (162.9 lb)
Engine:
Engine type Liquid cooled 2-stroke, gasoline
Cylinder arrangement Single cylinder, forward inclined
Displacement 84.7 cm
3 (2.98 Imp oz, 2.86 US oz)
Bore × stroke 47.5 × 47.8 mm (1.870 × 1.882 in)
Compression ratio 8.2 : 1
Starting system Kickstarter
Lubrication system: Premix (30 : 1) (Yamalube 2-R)
Oil type or grade (2-cycle):
Transmission oil Yamalube 4 (10W-30) or SAE 10W-30 type SE
motor oil
Periodic oil change 0.50 L (0.44 Imp qt, 0.52 US qt)
Total amount 0.55 L (0.48 Imp qt, 0.58 US qt)
Coolant capacity (including all routes): 0.54 L (0.48 Imp qt, 0.57 US qt)
Air filter: Wet type element
2

SPEC
2 - 2
GENERAL SPECIFICATIONS
Fuel:
Type Premium unleaded gasoline only with a
research octane number of 95 or higher.
(Except for ZA)
Premium gasoline (For ZA)
Tank capacity 5.0 L (1.10 Imp gal, 1.32 US gal)
Carburetor:
Type/manufacturer PWK28/KEIHIN
Spark plug:
Type/manufacturer BR10EG/NGK (resistance type)
Gap 0.5 ~ 0.6 mm (0.020 ~ 0.024 in)
Clutch type: Wet, multiple-disc
Transmission: YZ85 YZ85LW
Primary reduction system Gear←
Primary reduction ratio 65/18 (3.611)←
Secondary reduction system Chain drive←
Secondary reduction ratio 47/14 (3.357) 52/14 (3.714)
(USA, S, NZ, ZA)
48/14 (3.429)
(F, D, I, GB, E, CDN,
AUS)
Transmission type Constant mesh,
6-speed←
Operation Left foot operation←
Gear ratio: 1st 27/11 (2.454)←
2nd 32/17 (1.882)←
3rd 26/17 (1.529)←
4th 22/17 (1.294)←
5th 26/23 (1.130)←
6th 25/25 (1.000)←
Chassis: YZ85 YZ85LW
Frame type Semi double cradle←
Caster angle 26.3°26.9°
Trail 88 mm (3.46 in) 105.5 mm (4.15 in)
Tire: YZ85 YZ85LW
Type With tube←
Size (front) 70/100-17 40M 70/100-19 42M
Size (rear) 90/100-14 49M 90/100-16 52M
Tire pressure (front and rear) 100 kPa
(1.0 kgf/cm
2, 15 psi)←
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation

2

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses








Every two years
OUTSIDE NUTS AND BOLTS
Retighten



AIR FILTER
Clean and lubricate
Replace




Use foam air-filter oil or
equivalent oil
FRAME
Clean and inspect



FUEL TANK, COCK
Clean and inspect



BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper
bolts, master cylinder bolts and union
bolts
Replace pads
Replace brake fluid























Every one year
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal









Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube


Lithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten







(After
rain ride)


Molybdenum disulfide
grease
DRIVE CHAIN GUIDE, ROLLERS AND
SUPPORT
Inspect


SWINGARM
Inspect and retighten
Lube







Molybdenum disulfide
grease
RELAY ARM, CONNECTING ROD
Inspect and retighten
Lube







Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing







Lithium base grease ItemAfter
break-inEvery
raceEvery
third
raceEvery
fifth
raceAs re-
quiredRemarks


3

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh mixture of oil and gasoline is filled in the fuel
tank. Check the fuel line for leakage.P.1-12
Transmission oilCheck that the oil level is correct. Check the crankcase for leak-
age.P.3-12 ~ 13
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10
Brakes Check the play of front brake and effect of front and rear brake. P.3-16 ~ 21
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-22 ~ 24
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-31 ~ 32
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-32 ~ 34
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-24 ~ 30
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Exhaust pipe and silencerCheck that the exhaust pipe is tightly mounted and has no
cracks.P.4-2
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-22
Lubrication Check for smooth operation. Lubricate if necessary. P.3-35
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-16
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 19

4 - 49
ENG
EC4M0000
ENGINE REMOVAL
5PA41490
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for removal Hold the machine by placing the
suitable stand under the frame.
WARNING
Support the machine securely so there is no
danger of it falling over.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Carburetor Refer to “CARBURETOR AND REED
VALVE” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Clutch cable Disconnect at engine side.
Radiator hose 1 Disconnect at cylinder head side.
Radiator hose 2 Disconnect at water pump side.
Spark plug cap
Disconnect the CDI magneto
lead.
ENGINE REMOVAL

6 - 2
–+ELECIGNITION 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.
*marked: Only when the ignition checker is used.
NOTE:

Remove the following parts before inspection.
1) Seat
2) Fuel tank

Use the following special tools in this inspection.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754Pocket tester:
YU-3112-C/90890-03112
Spark gap test*Clean or replace
spark plug.
Check entire ignition
system for connection.Repair or replace.
Check engine stop switch. Replace.
Check ignition coil. Primary coil Replace.
Secondary coil Replace.
Check spark plug cap. Replace.
Check CDI magneto. Pickup coil Replace.
Charging 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
No good