EAS2GC1005
SAFETY INFORMATION
THIS MACHINE IS DESIGNED STRICTLY FOR COMPETITION USE, ONLY ON A CLOSED
COURSE. It is illegal for this machine to be operat ed on any public street, road, or highway. Off-road
use on public lands may also be illegal. Pl ease check local regulations before riding.
• THIS MACHINE IS TO BE OPERATED BY AN EXPERIENCED RIDER ONLY. Do not attempt to operate this machine at maximum power until you are totally familiar with its char-
acteristics.
• THIS MACHINE IS DESIGNED TO BE RIDDEN BY THE OPERATOR ONLY. Do not carry passengers on this machine.
• ALWAYS WEAR PROTECTIVE APPAREL. When operating this machine, always wear an approved helmet with goggles or a face shield. Also
wear heavy boots, gloves, and protective clothing. Al ways wear proper fitting clothing that will not
be caught in any of the moving parts or controls of the machine.
• ALWAYS MAINTAIN YOUR MACHINE IN PROPER WORKING ORDER. For safety and reliability, the machine must be properly maintained. Always perform the pre-oper-
ation checks indicated in this manual.
Correcting a mechanical problem before you ride may prevent an accident.
• GASOLINE IS HIGHLY FLAMMABLE. Always turn off the engine while refueling. Take care to not spill any gasoline on the engine or ex-
haust system. Never refuel in the vicini ty of an open flame, or while smoking.
• GASOLINE CAN CAUSE INJURY. If you should swallow some gasoline, inhale excess gasoline vapors, or allow any gasoline to get
into your eyes, contact a doctor immediately. If any gasoline spills onto your skin or clothing, imme-
diately wash skin areas with soap and water, and change your clothes.
• ONLY OPERATE THE MACHINE IN AN AREA WITH ADEQUATE VENTILATION.
Never start the engine or let it run for any length of time in an enclosed area. Exhaust fumes are
poisonous. These fumes contain carbon monoxide, whic h by itself is odorless and colorless. Car-
bon monoxide is a dangerous gas which can cause unconsciousness or can be lethal.
• PARK THE MACHINE CAREFULLY; TURN OFF THE ENGINE. Always turn off the engine if you are going to leave the machine. Do not park the machine on a slope
or soft ground as it may fall over.
• THE ENGINE, EXHAUST PIPE AND MUFFLER WILL BE VERY HOT AFTER THE ENGINE HAS BEEN RUN.
Be careful not to touch them or to allow any clothing item to contact them during inspection or repair.
• PROPERLY SECURE THE MACHINE BEFORE TRANSPORTING IT. For safety, drain the gasoline from the fuel tank before transporting the vehicle.
STARTING AND BREAK-IN
1-28
EAS2GC1048
STARTING AND BREAK-IN
EAS2GC1049FUEL
Always use the recommended fuel as stated
below. Also, be sure to use new gasoline the
day of a race.
ECA
NOTICE
Use only unleaded gasoline. The use of
leaded gasoline will cause severe damage
to the engine internal parts such as valves,
piston rings, and exhaust system, etc.
TIP
Your Yamaha engine has been designed to use
premium unleaded gasoline with a pump oc-
tane number [(R+M)/2] of 91 or higher, or a re-
search octane number of 95 or higher. If
knocking (or pinging) occurs, use a gasoline of
a different brand.
EWA
WARNING
• For refueling, be sure to stop the engine and use enough care not to spill any fuel.
Also be sure to avoid refueling close to a
fire.
• Refuel after the engine, exhaust pipe, etc.
have cooled off.
Gasohol (For USA and Canada)
There are two types of gasohol: gasohol con-
taining ethanol and that containing methanol.
Gasohol containing ethanol can be used if the
ethanol content does not exceed 10%. Gasohol
containing methanol is not recommended by
Yamaha because it can cause damage to the
fuel system or vehicle performance problems.
EAS2GC1050HANDLING NOTEEWA
WARNING
Never start or run the engine in a closed ar-
ea. The exhaust fumes are poisonous; they
can cause loss of consciousness and death
in a very short time. Always operate the ma-
chine in a well-ventilated area.
ECA
NOTICE
• Unlike a two-stroke engine, this engine cannot be kick started when the throttle is
open because the kickstarter may kick
back. Also, if the throttle is open the air/
fuel mixture may be too lean for the engine
to start.
• Before starting the machine, perform the
checks in the pre-operation check list.
EAS2GC1051AIR FILTER MAINTENANCE
According to “CLEANING THE AIR FILTER
ELEMENT” section in the CHAPTER 3, apply
the Yamaha foam air filter oil or other quality
foam air filter oil to the element. (Excess oil in
the element may adversely affect engine start-
ing.)
EAS2GC1052STARTING A COLD ENGINEECA
NOTICE
For maximum engine life, never accelerate
hard when the engine is cold!
In order for the ignition circuit cut-off system to
enable starting, one of the following conditions
must be met:
• The transmission is in the neutral position.
• The transmission is in gear with the clutch le- ver pulled.
1. Pull the starter knob/idle screw “1” to its full length.
TIP
When the ambient temperature is 15°C (59°F)
or below, use the starter knob/idle screw.
2. Completely close the throttle.
3. Start the engine by pushing the start switch.If the engine fails to start when using the
start switch, release it, wait a few seconds,
and then try again.
Each starting attempt should be as short as
possible to preserve the battery. Do not
crank the engine more than 10 seconds on
any one attempt. If the engine does not start
with the starter motor, try using the kickstart-
er.
Recommended fuel
Premium unleaded gasoline
only
Fuel tank capacity 7.5 L (2.0 US gal, 1.7 lmp.gal)
Fuel reserve amount 2.0 L (0.5 US gal, 0.4 Imp.gal)
1
GENERAL SPECIFICATIONS
2-1
EAS2GC1061
GENERAL SPECIFICATIONS
ModelModel 2GC1 (USA) 2GC2 (CAN)
2GC3 (EUR)
2GC4, 2GC5 (AUS) (NZL) (ZAF)
DimensionsOverall length 2165 mm (85.2 in)
Overall width 825 mm (32.5 in)
Overall height 1280 mm (50.4 in)
Seat height 965 mm (38.0 in)
Wheelbase 1465 mm (57.7 in)
Ground clearance 325 mm (12.80 in)
WeightCurb weight 123 kg (271 lb)
ENGINE SPECIFICATIONS
2-4
Valve springFree length (intake) 40.76 mm (1.60 in)
Limit 38.72 mm (1.52 in)
Free length (exhaust) 36.94 mm (1.45 in)
Limit 35.09 mm (1.38 in)
Installed length (intake) 34.78 mm (1.37 in)
Installed length (exhaust) 30.83 mm (1.21 in)
Spring rate K1 (intake) 31.90 N/mm (3.25 kgf/mm, 182.15 lbf/in)
Spring rate K2 (intake) 41.37 N/mm (4.22 kgf/mm, 236.22 lbf/in)
Spring rate K1 (exhaust) 21.76 N/mm (2.22 kgf/mm, 124.25 lbf/in)
Spring rate K2 (exhaust) 28.12 N/mm (2.87 kgf/mm, 160.57 lbf/in)
Installed compression spring force (intake) 178.00–204.00 N (18.15–20.80 kgf,
40.01–45.86 lbf)
Installed compression spring force (exhaust) 124.00–142.00 N (12.64–14.48 kgf,
27.88–31.92 lbf)
Spring tilt (intake) 2.5 °/1.8 mm (2.5 °/0.07 in)
Spring tilt (exhaust) 2.5 °/1.6 mm (2.5 °/0.06 in)
Winding direction (intake) Clockwise
Winding direction (exhaust) Clockwise
Cylinder Bore 97.000–97.010 mm (3.8189–3.8193 in)
Taper limit 0.050 mm (0.0020 in)
Out of round limit 0.050 mm (0.0020 in)
PistonPiston-to-cylinder clearance 0.030–0.055 mm (0.0012–0.0022 in)
Limit 0.15 mm (0.006 in)
Diameter 96.955–96.970 mm (3.8171–3.8177 in)
Measuring point (from piston skirt bottom) 9.0 mm (0.35 in)
Offset 0.00 mm (0.0000 in)
Piston pin bore inside diameter 18.004–18.015 mm (0.7088–0.7093 in)
Limit 18.045 mm (0.7104 in)
Piston pin outside diameter 17.991–18.000 mm (0.7083–0.7087 in)
Limit 17.971 mm (0.7075 in)
Piston ringTop ring Ring type Barrel
Dimensions (B T) 1.00 3.30 mm (0.04 0.13 in)
End gap (installed) 0.20–0.30 mm (0.0079–0.0118 in)
Limit 0.55 mm (0.0217 in)
Ring side clearance 0.015–0.065 mm (0.0006–0.0026 in)
Limit 0.120 mm (0.0047 in)
2nd ring Ring type Taper
Dimensions (B T) 1.00 3.10 mm (0.04 0.12 in)
End gap (installed) 0.35–0.50 mm (0.0138–0.0197 in)
Limit 0.85 mm (0.0335 in)
Ring side clearance 0.020–0.060 mm (0.0008–0.0024 in)
Limit 0.120 mm (0.0047 in)
Oil ring
Dimensions (B T) 1.50 2.25 mm (0.06 0.89 in)
End gap (installed) 0.20–0.50 mm (0.0079–0.0197 in)
ENGINE SPECIFICATIONS
2-5
CrankshaftCrank assembly width 61.93–62.00 mm (2.438–2.441 in)
Runout limit 0.030 mm (0.0012 in)
Big end side clearance 0.150–0.450 mm (0.0059–0.0177 in)
BalancerBalancer drive method Gear
ClutchClutch type Wet, multiple-disc
Clutch release method Inner push, cam push
Clutch lever free play 7.0–12.0 mm (0.28–0.47 in)
Friction plate 1 thickness 2.92–3.08 mm (0.115–0.121 in)
Wear limit 2.85 mm (0.112 in)
Plate quantity 3 pcs
Friction plate 2 thickness 2.92–3.08 mm (0.115–0.121 in)
Wear limit 2.85 mm (0.112 in)
Plate quantity 5 pcs
Clutch plate 1 thickness 1.90–2.10 mm (0.075–0.083 in)
Plate quantity 4 pcs
Warpage limit 0.10 mm (0.004 in)
Clutch plate 2 thickness 1.50–1.70 mm (0.059–0.067 in)
Plate quantity 3 pcs
Warpage limit 0.10 mm (0.004 in)
Clutch spring free length 50.00 mm (1.97 in)
Limit 47.50 mm (1.87 in)
Spring quantity 6 pcs
Push rod bending limit 0.10 mm (0.004 in)
TransmissionTransmission type Constant mesh 5-speed
Primary reduction system Spur gear
Primary reduction ratio 2.609 (60/23)
Final drive Chain
Secondary reduction ratio 3.846 (50/13)
Operation Left foot operation
Gear ratio
1st 2.417 (29/12)
2nd 1.733 (26/15)
3rd 1.313 (21/16)
4th 1.050 (21/20)
5th 0.840 (21/25)
Main axle runout limit 0.08 mm (0.0032 in)
Drive axle runout limit 0.08 mm (0.0032 in)
Shifting mechanism
Shift mechanism type Shift drum and guide bar
Shift fork guide bar bending limit 0.050 mm (0.0020 in)
Shift fork thickness 4.85 mm (0.1909 in)
Decompression deviceDevice type Auto decomp
Air filterAir filter element Wet element
Air filter oil grade Yamaha foam air filter oil or other quality foam air filter oil
CHASSIS SPECIFICATIONS
2-8
Rear brakeType Hydraulic single disc brake
Operation Right foot operation
Brake pedal position 5.0 mm (0.20 in)
Rear disc brake
Disc outside diameter thickness 245.0 4.0 mm (9.65 0.16 in)
Brake disc thickness limit 3.5 mm (0.14 in)
Brake disc runout limit (as measured on wheel) 0.15 mm (0.0059 in)
Brake pad lining thickness 6.4 mm (0.25 in)
Limit 1.0 mm (0.04 in)
Master cylinder inside diameter 11.0 mm (0.43 in)
Caliper cylinder inside diameter 25.40 mm (1.00 in)
Specified brake fluid DOT 4
Steering Steering bearing type Taper roller bearing
Center to lock angle (left) 43.0 °
Center to lock angle (right) 43.0 °
Front suspension
Type Telescopic fork
Spring/shock absorber type Coil spring/Hydraulic damper
Front fork travel 310.0 mm (12.20 in)
Fork spring free length 470.0 mm (18.50 in)
Limit 465.0 mm (18.31 in)
Fork spring installed length 470.0 mm (18.50 in)
Spring rate K1 4.50 N/mm (0.46 kgf/mm, 25.71 lbf/in)
Spring stroke K1 0.0–310.0 mm (0.00–12.20 in)
Inner tube outer diameter 48 mm (1.9 in)
Inner tube bending limit 0.2 mm (0.01 in)
Optional spring available Yes
Recommended oil Yamaha Suspension Oil S1
Quantity 545.0 cm
3 (18.43 US oz, 19.18 Imp.oz)
Rebound damping adjusting positions
Minimum 20 clicks out*
Standard 11 clicks out*
Maximum Fully turned in * With the adjuster fully turned in
Compression damping adjusting positions Minimum 20 clicks out*
Standard 13 clicks out*
Maximum Fully turned in
* With the adjuster fully turned in
CHASSIS SPECIFICATIONS
2-9
Rear suspensionType Swingarm (link suspension)
Spring/shock absorber type Coil spring/Gas-hydraulic damper
Rear shock absorber assembly travel 126.0 mm (4.96 in)
Spring free length 275.0 mm (10.83 in)
Spring installed length 263.0 mm (10.35 in)
Spring rate K1 56.00 N/mm (5.71 kgf/mm, 319.76 lbf/in)
Spring stroke K1 0.0–150.0 mm (0.00–5.91 in)
Optional spring available Yes
Enclosed gas/air pressure (STD) 980 kPa (9.8 kgf/cm
2, 139.4 psi)
Spring preload adjusting positions
Minimum Position in which the spring is turned in 1.5 mm
(0.06 in) from its free length.
Standard Position in which the spring is turned in 12 mm
(0.47 in) from its free length.
Maximum Position in which the spring is turned in 18 mm
(0.71 in) from its free length.
Rebound damping adjusting positions Minimum 30 clicks out*
Standard 14 clicks out*
Maximum Fully turned in
* With the adjuster fully turned in
Compression damping setting
(for fast compression damping)Minimum 2 turns out*
Standard 1-3/4 turns out*
Maximum Fully turned in
* With the adjuster fully turned in
Compression damping setting
(for slow compression damping)Minimum 20 clicks out*
Standard 10 clicks out*
Maximum Fully turned in
* With the adjuster fully turned in
Swingarm Swingarm end free play limit (radial) 1.0 mm (0.04 in)
Swingarm end free play limit (axial) 0.2–0.9 mm (0.01–0.04 in)
Drive chainSize/manufacturer DID520VM2/DAIDO
Number of links 114
Drive chain slack (on a suitable stand) 50.0–60.0 mm (1.97–2.36 in)
15-link length limit 239.3 mm (9.42 in)
ELECTRICAL SPECIFICATIONS
2-11
Starter motorPower output 0.48 kW
Armature coil resistance 0.0117–0.0143
Brush overall length 7.0 mm (0.28 in)
Limit 3.50 mm (0.14 in)
Brush spring force 3.92–5.88 N (400–600 gf, 14.11–21.17 oz)
Commutator diameter 17.6 mm (0.69 in)
Limit 16.6 mm (0.65 in)
Mica undercut (depth) 1.50 mm (0.06 in)
Starter relay Amperage 180.0 A
Coil resistance 4.18–4.62
Starting circuit cut-off relay
Coil resistance 75.7–92.5
Headlight relay
Coil resistance 75.7–92.5
Fuses
Main fuse 15.0 A
Radiator fan motor fuse 5.0 A
Spare fuse 15.0 A