2002 YAMAHA YZ85 brake

CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL....... 5-1
FRONT BRAKE AND REAR BRAKE....... 5-9
FRONT FORK.......................................... 5-27
HANDLEBAR........................................... 5-41
STEERING............................................... 5-46
SWINGARM............................................. 5-51
REAR SHOCK ABSORBER.................... 5-59
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM........................... 6-1
IGNITION SYSTEM.................................... 6-2
CHAPTER 7
TUNING
ENGINE...................................................... 7-1
CHASSIS................................................. 7-10

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:
lThe machine you have purchased may differ
slightly from those shown in the following.
lDesigns and specifications are subject to
change without notice.
5PA10020
5PA10010
5PA10030
1

1 - 10
GEN
INFO
CONTROL FUNCTIONS
EC156000
FRONT BRAKE LEVER
The front brake lever 1 is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
5PA10470
EC157000
REAR BRAKE PEDAL
The rear brake pedal 1 is located on the right
side of the machine. Press down on the brake
pedal to activate the rear brake.
5PA10480
EC158001
FUEL COCK
The fuel cock supplies fuel from the tank to
carburetor while filtering the fuel. The fuel cock
has the two positions:
OFF:With the lever in this position, fuel will not
flow. Always return the lever to this posi-
tion when the engine is not running.
ON: With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
5PA10490
EC159000
STARTER KNOB (CHOKE)
When cold, the engine requires a richer air-fuel
mixture for starting. A separate starter circuit,
which is controlled by the starter knob 1, sup-
plies this mixture. Pull the starter knob out to
open the circuit for starting. When the engine
has warmed up, push it in to close the circuit.
5PA10500

GEN
INFO
1 - 16
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Frame construction
Combined seat and fuel tank
Engine mounting
Steering Steering stem to
handlebar
Suspension Front Steering stem to front
fork
Rear For link type
Rear Installation of rear
shock absorber
Rear Installation of swin-
garm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel systemFrame to rear frame
Fuel tank to frame
Frame to engine
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Rear shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of wheel axle
Wheel to rear wheel sprocket
Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Brake caliper to bracket
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.

1 - 17
GEN
INFO
CLEANING AND STORAGE
EC1B0000
CLEANING AND STORAGE
EC1B1000
CLEANING
Frequent cleaning of your machine will
enhance its appearance, maintain good overall
performance, and extend the life of many com-
ponents.
1. Before washing the machine, block off the
end of the exhaust pipe to prevent water
from entering. A plastic bag secured with a
rubber band may be used for this purpose.
2. If the engine is excessively greasy, apply
some degreaser to it with a paint brush. Do
not apply degreaser to the chain, sprock-
ets, or wheel axles.
3. Rinse the dirt and degreaser off with a gar-
den hose; use only enough pressure to do
the job.
CAUTION:
Excessive hose pressure may cause water
seepage and contamination of wheel bear-
ings, front forks, brakes and transmission
seals. Many expensive repair bills have
resulted from improper high pressure
detergent applications such as those avail-
able in coin-operated car washers.
4. After the majority of the dirt has been
hosed off, wash all surfaces with warm
water and a mild detergent. Use an old
toothbrush to clean hard-to-reach places.
5. Rinse the machine off immediately with
clean water, and dry all surfaces with a soft
towel or cloth.
6. Immediately after washing, remove excess
water from the chain with a paper towel
and lubricate the chain to prevent rust.
7. Clean the seat with a vinyl upholstery
cleaner to keep the cover pliable and
glossy.
8. Automotive wax may be applied to all
painted or chromed surfaces. Avoid combi-
nation cleaner-waxes, as they may contain
abrasives.
9. After completing the above, start the
engine and allow it to idle for several min-
utes.

SPEC
2 - 2
GENERAL SPECIFICATIONS
Fuel:
Type Premium unleaded gasoline only with a
research octane number of 95 or higher.
Tank capacity 5.0 L (1.10 Imp gal, 1.32 US gal)
Carburetor:
Type/manufacturer PWK28/KEIHIN
Spark plug:
Type/manufacturer BR10EG/NGK
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° 27°
Trail 88 mm (3.46 in) 106 mm (4.17 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 kg/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
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)

2

SPEC
2 - 9
MAINTENANCE SPECIFICATIONS
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/material 17 ´ 1.40/Aluminum ----
Rear rim size/material 14 ´ 1.60/Aluminum ----
Rim runout limit:
Radial ---- 2.0 mm (0.08 in)
Lateral ---- 2.0 mm (0.08 in)
Drive chain:
Type/manufacturer DID428DS/DAIDO ----
Number of links 117 links + joint ----
Chain slack 35 ~ 45 mm (1.4 ~ 1.8 in) ----
Chain length (10 links) ---- 122.1 mm (4.81 in)
Front disc brake:
Disc outside dia. ´ Thickness 220 ´ 3.0 mm (8.66 ´ 0.12 in) 220 ´ 2.5 mm
(8.66 ´ 0.10 in)
Deflection limit ---- 0.15 mm (0.006 in)
Pad thickness 4.0 mm (0.16 in) 0.8 mm (0.03 in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 22.22 mm (0.875 in) ´ 2 ----
Brake fluid type DOT #4 ----
Rear disc brake:
Disc outside dia. ´ Thickness 190 ´ 3.0 mm (7.84 ´ 0.12 in) 190 ´ 2.5 mm
(7.84 ´ 0.12 in)
Deflection limit ---- 0.15 mm (0.006 in)
Pad thickness 3.7 mm (0.15 in) 1.0 mm (0.04 in)
Master cylinder inside dia. 12.7 mm (0.500 in) ----
Caliper cylinder inside dia. 27.0 mm (1.063 in) ´ 1 ----
Brake fluid type DOT #4 ----
Brake lever and brake pedal:
Brake lever position 95 mm (3.74 in) ----
Brake pedal height
(vertical height below footrest top)7 mm (0.28 in) ----
Clutch lever free play 10 ~ 15 mm (0.39 ~ 0.59 in) ----
Throttle grip free play 3 ~ 5 mm (0.12 ~ 0.20 in) ----Item Standard Limit

SPEC
2 - 11
MAINTENANCE SPECIFICATIONS
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/material 19 ´ 1.40/Aluminum ----
Rear rim size/material 16 ´ 1.85/Aluminum ----
Rim runout limit:
Radial ---- 2.0 mm (0.08 in)
Lateral ---- 2.0 mm (0.08 in)
Drive chain:
Type/manufacturer DID428DS/DAIDO ----
Number of links 121 links + joint ----
Chain slack 35 ~ 45 mm (1.4 ~ 1.8 in) ----
Chain length (10 links) ---- 122.1 mm (4.81 in)
Front disc brake:
Disc outside dia. ´ Thickness 220 ´ 3.0 mm (8.66 ´ 0.12 in) 220 ´ 2.5 mm
(8.66 ´ 0.10 in)
Deflection limit ---- 0.15 mm (0.006 in)
Pad thickness 4.0 mm (0.16 in) 0.8 mm (0.03 in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 22.22 mm (0.875 in) ´ 2 ----
Brake fluid type DOT #4 ----
Rear disc brake:
Disc outside dia. ´ Thickness 190 ´ 3.0 mm (7.84 ´ 0.12 in) 190 ´ 2.5 mm
(7.84 ´ 0.12 in)
Deflection limit ---- 0.15 mm (0.006 in)
Pad thickness 3.7 mm (0.15 in) 1.0 mm (0.04 in)
Master cylinder inside dia. 12.7 mm (0.500 in) ----
Caliper cylinder inside dia. 27.0 mm (1.063 in) ´ 1 ----
Brake fluid type DOT #4 ----
Brake lever and brake pedal:
Brake lever position 95 mm (3.74 in) ----
Brake pedal height
(vertical height below footrest top)5 mm (0.20 in) ----
Clutch lever free play 10 ~ 15 mm (0.39 ~ 0.59 in) ----
Throttle grip free play 3 ~ 5 mm (0.12 ~ 0.20 in) ----Item Standard Limit