Yamaha Fz1n Service Manual

							
FEATURES
1-2
EAS20170
FEATURES
OUTLINE OF THE FI SYSTEM
The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti-
mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera-
ture. In the conventional carburetor system, the air-fuel ratio of the mixture that is supplied to the 
combustion chamber is created by the volume of the intake air and the fuel that is metered by the jet 
used in the respective carburetor.
Despite the same volume of intake air, the fuel volume requirement varies by the engine operating 
conditions, such as acceleration, deceleration, or operating under a heavy load. Carburetors that 
meter the fuel through the use of jets have been provided with various auxiliary devices, so that an 
optimum air-fuel ratio can be achieved to accommoda te the constant changes in the operating con-
ditions of the engine.
As the requirements for the engine to deliver  more performance and cleaner exhaust gases 
increase, it becomes necessary to control the air-f uel ratio in a more precise and finely tuned man-
ner. To accommodate this need, this model has adopt ed an electronically controlled fuel injection 
(FI) system, in place of the conventional carbur etor system. This system can achieve an optimum 
air-fuel ratio required by the engine at all times  by using a microprocessor that regulates the fuel 
injection volume according to the engine operating conditions detected by various sensors.
The adoption of the FI system has resulted in a highly precise fuel supply, improved engine 
response, better fuel economy, and reduced exhaust emissions.
1. Ignition coil
2. Air filter case
3. Intake air temperature sensor
4. Fuel delivery hose
5. Fuel tank
6. Fuel pump
7. Intake air pressure sensor
8. Throttle position sensor
9. Sub-throttle position sensor
10.Fuel injector
11.Catalytic converter
12.Crankshaft position sensor
13.Coolant temperature sensor 14.Spark plug
15.Cylinder identification sensor
16.Battery
17.ECU
18.Atomospheric pressure sensor
19.Relay unit (fuel pump relay)
20.Engine trouble warning light
21.Lean angle sensor
22.Air cut-off valve
23.O
2 sensor 
						

							
FI SYSTEM
1-3
ET2D1001
FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains the 
fuel pressure that is applied to the fuel injector at only 324 kPa (3.24 kg/cm
2, 46.1 psi). Accordingly, 
when the energizing signal from the ECU energize s the fuel injector, the fuel passage opens, caus-
ing the fuel to be injected into the intake manifo ld only during the time the passage remain open. 
Therefore, the longer the length of time the fuel injector is energized (injection duration), the greater 
the volume of fuel that is supplied. Conversely, the  shorter the length of time the fuel injector is ener-
gized (injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals that are input from 
the throttle position sensor, crankshaft position sens or, intake air pressure sensor, air temperature 
sensor, coolant temperature sensor, speed sensor and O
2 sensor enable the ECU to determine the 
injection duration. The injection timing is det ermined through the signals from the crankshaft posi-
tion sensor. As a result, the volume of fuel that  is required by the engine can be supplied at all times 
in accordance with the driving conditions.
Illustration is for reference only.
1. Fuel pump
2. Fuel injector
3. Ignition coil
4. ECU (engine control unit)
5. Intake air temperature sensor
6. Throttle position sensor
7. Sub-throttle position sensor
8. O
2 sensor
9. Catalytic converter
10.Coolant temperature sensor
11.Crankshaft position sensor
12.Intake air pressure sensor 13.Throttle body
14.Air filter case
A. Fuel system
B. Air system
C. Control system 
						

							
INSTRUMENT FUNCTIONS
1-4
ET2D1002
INSTRUMENT FUNCTIONS
Multi-function meter unit
WARNING
EW2D1005
Be sure to stop the vehicle before making 
any setting changes to the multi-function 
meter unit.
The multi-function meter unit is equipped with 
the following:
 a speedometer (which shows the riding speed)
 a tachometer (which shows engine speed)
 an odometer (which shows the total distance  traveled)
 two tripmeters (which show the distance trav-
eled since they were last set to zero)
 a fuel reserve tripmeter (which shows the  distance traveled since the left segment of 
the fuel meter started flashing)
a clock
 a fuel meter
 a coolant temperature display
 an air intake temperature display
 a self-diagnosis device
 an LCD and tachometer brightness control  mode
NOTE:
 Be sure to turn the ke y to “ON” before using 
the “SELECT” and “RESET” buttons.
 For the U.K. only: To switch the speedometer  and odometer/tripmeter displays between  kilometers and miles, press the “SELECT” 
button for at least one second.
Tachometer
The electric tachometer allows the rider to 
monitor the engine speed and keep it within 
the ideal power range.
When the key is turned to “ON”, the tachome-
ter needle will sweep once across the r/min 
range and then return to zero r/min in order to 
test the electrical circuit.
CAUTION:
EC2D1007
Do not operate the engine in the tachome-
ter red zone.
Red zone: 12000 r/min and above
Clock mode
The clock is displayed when the key is turned 
to “ON”. In addition, the clock can be displayed 
for 10 seconds by pushing the “SELECT” but-
ton when the main switch is in the “OFF” or 
“LOCK” position.
To set the clock
1. Turn the key to “ON”.
2. Push the “SELECT” button and “RESET”  button together for at least two seconds.
1. Coolant temperature display/air intake tem-perature display
2. Speedometer
3. Tachometer
4. Odometer/tripmeter/fuel reserve tripmeter
5. “SELECT” button
6. “RESET” button
7. Clock
8. Fuel meter1. Tachometer
2. Tachometer red zone
1. Clock
2. Speedometer 
						

							
INSTRUMENT FUNCTIONS
1-5
3. When the hour digits start flashing, push the “RESET” button to set the hours.
4. Push the “SELECT” button, and the minute  digits will start flashing.
5. Push the “RESET” button to set the min-
utes.
6. Push the “SELECT” button and then  release it to start the clock.
Odometer and tripmeter modes
Push the “SELECT” button to switch the dis-
play between the odometer mode “ODO” and 
the tripmeter modes “TRIP A” and “TRIP B” in 
the following order:
TRIP A  → TRIP B  → ODO  → TRIP A
When the fuel amount in the fuel tank 
decreases to 3.4 L (0.90 US gal) (0.75 
Imp.gal), the left segment of the fuel meter will 
start flashing, and the odometer display will 
automatically change to the fuel reserve trip-
meter mode “FTRIP” and start counting the 
distance traveled from that point. In that case, 
push the “SELECT” button to switch the dis-
play between the various tripmeter and odom-
eter modes in the following order:
F-TRIP  → TRIP A  → TRIP B  → ODO  → F-
TRIP
To reset a tripmeter, select it by pushing the 
“SELECT” button, and then push the “RESET” 
button for at least one second. If you do not 
reset the fuel reserve tripmeter manually, it will 
reset itself automatically and the display will 
return to the prior mode after refueling and 
traveling 5 km (3 mi).
Fuel meter The fuel meter indicates the amount of fuel in 
the fuel tank. The display segments of the fuel 
meter disappear towards “E” (Empty) as the 
fuel level decreases. When only one segment 
is left near “E”, refuel as soon as possible.
NOTE:
This fuel meter is equipped with a self-diagno-
sis system. If the electrical circuit is defective, 
the following cycle will be repeated until the 
malfunction is corrected: “E” (Empty), “F” (Full) 
and symbol “ ” will flash eight times, then go 
off for approximately 3 seconds. If this occurs, 
have a Yamaha dealer check the electrical cir-
cuit.
Coolant temperature mode
The coolant temperature display indicates the 
temperature of the coolant.
Push the “RESET” button to switch the coolant 
temperature display to the air intake tempera-
ture display.
NOTE:
When the coolant temperature display is 
selected, “C” is displayed for one second, and 
then the coolant temperature is displayed.
CAUTION:
EC2D1011
Do not operate the engine if it is over-
heated.
1. Odometer/tripmeter/fuel reserve tripmeter
1. Fuel meter
1. Coolant temperature display 
						

							
INSTRUMENT FUNCTIONS
1-6
Air intake temperature mode
The air intake temperature display indicates 
the temperature of the air drawn into the air fil-
ter case. Push the “RESET” button to switch 
the coolant temperature display to the air 
intake temperature display.
NOTE:
 Even if the air intake temperature is set to be displayed, the coolant temperature warning 
light comes on when the engine overheats.
 When the key is turned to “ON”, the coolant  temperature is automatically displayed, even 
if the air intake temperature was displayed 
prior to turning the key to “OFF”.
 When the air intake temperature display is  selected, “A” is displayed for one second, 
and then the air intake temperature is dis-
played.
Self-diagnosis device
This model is equipped with a self-diagnosis 
device for various electrical circuits.
If any of those circuits are defective, the engine 
trouble warning light will come on, and then the 
display will indicate a tw o-digit error code (e.g., 
11, 12, 13).
This model is also equipped with a self-diagno-
sis device for the immobilizer system.
If any of the immobilizer system circuits are 
defective, the immobilizer system indicator  light will flash, and then 
the display will indicate 
a two-digit error code (e.g., 51, 52, 53).
NOTE:
If the display indicates error code 52, this could 
be caused by transponder interference. If this 
error code appears, try the following.
1. Use the code re-registering key to start the  engine.
NOTE:
Make sure there are no other immobilizer keys 
close to the main switch, and do not keep more 
than one immobilizer key on the same key ring! 
Immobilizer system keys may cause signal 
interference, which may prevent the engine 
from starting
2. If the engine starts, turn it off and try start-
ing the engine with the standard keys.
3. If one or both of the standard keys do not 
start the engine, take the vehicle, the code 
re-registering key and both standard keys 
to a Yamaha dealer and have the standard 
keys re-registered.
If the display indicates any error codes, note 
the code number, and then have a Yamaha 
dealer check the vehicle.
CAUTION:
EC2D1012
If the display indicates an error code, the 
vehicle should be checked as soon as pos-
sible in order to avoid engine damage.
LCD and tachometer brightness control
mode
This function allows you to adjust the bright-
ness of the LCD and the tachometer panel and 
needle to suit the outside lighting conditions.
To set the brightness
1. Air intake temperature display
1. Error code display
1. Tachometer panel
2. Tachometer needle
3. LCD
4. Brightness level 
						

							
INSTRUMENT FUNCTIONS
1-7
1. Turn the key to “OFF”.
2. Push and hold the “SELECT” button.
3. Turn the key to “ON”, and then release the “SELECT” button after five seconds.
4. Push the “RESET” button to select the 
desired brightness level.
5. Push the “SELECT” button to confirm the  selected brightness level. The display will 
return to the odometer or tripmeter mode. 
						

							
IMPORTANT INFORMATION
1-8
EAS20180
IMPORTANT INFORMATION
EAS20190
PREPARATION FOR REMOVAL AND DISAS-
SEMBLY
1. Before removal and disassembly, remove all dirt, mud, dust and foreign material.
2. Use only the proper tools and cleaning  equipment.
Refer to SPECIAL TOOLS on page 1-11.
3. When disassembling, always keep mated  parts together. This includes gears, cylin-
ders, pistons and other parts that have 
been “mated” through normal wear. Mated 
parts must always be reused or replaced 
as an assembly.
4. During disassembly, clean all of the parts  and place them in trays in the order of dis-
assembly. This will speed up assembly and 
allow for the correct installation of all parts.
5. Keep all parts away from any source of fire.
EAS20200
REPLACEMENT PARTS
Use only genuine Yamaha parts for all replace-
ments. Use oil and grease recommended by 
Yamaha for all lubrication jobs. Other brands 
may be similar in function and appearance, but 
inferior in quality.
EAS20210
GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all  gaskets, seals and O-rings. All gasket sur-
faces, oil seal lips and O-rings must be 
cleaned.
2. During reassembly, properly oil all mating 
parts and bearings and lubricate the oil 
seal lips with grease.
EAS20220
LOCK WASHERS/PLATES AND COTTER 
PINS
After removal, replace all lock washers/plates 
“1” and cotter pins. After the bolt or nut has 
been tightened to specification, bend the lock 
tabs along a flat of the bolt or nut.
1. Oil
2. Lip
3. Spring
4. Grease 
						

							
IMPORTANT INFORMATION
1-9
EAS20230
BEARINGS AND OIL SEALS
Install bearings “1” and oil seals “2” so that the 
manufacturer’s marks or numbers are visible. 
When installing oil seals, lubricate the oil seal 
lips with a light coat of lithium-soap-based 
grease. Oil bearings liberally when installing, if 
appropriate.
CAUTION:
ECA13300
Do not spin the bearing with compressed 
air because this will damage the bearing 
surfaces.
EAS20240
CIRCLIPS
Before reassembly, check all circlips carefully 
and replace damaged or distorted circlips. 
Always replace piston pin clips after one use. 
When installing a circlip “1”, make sure the 
sharp-edged corner “2” is positioned opposite 
the thrust “3” that the circlip receives. 
						

							
CHECKING THE CONNECTIONS
1-10
EAS20250
CHECKING THE CONNECTIONS
Check the leads, couplers, and connectors for 
stains, rust, moisture, etc.
1. Disconnect: Lead
 Coupler
 Connector
2. Check:
 Lead
 Coupler
 ConnectorMoisture  → Dry with an air blower.
Rust/stains  → Connect and disconnect 
several times.
3. Check:  All connections
Loose connection  → Connect properly.
NOTE:
If the pin “1” on the terminal is flattened, bend 
it up.
4. Connect:
 Lead
 Coupler
 Connector
NOTE:
Make sure all connections are tight.
5. Check:
 Continuity(with the pocket tester)
NOTE:
 If there is no continuity, clean the terminals.
 When checking the wire harness, perform 
steps (1) to (3).
 As a quick remedy, use a contact revitalizer 
available at most part stores.
Pocket tester
90890-03112
Analog Pocket tester
YU-03112-C 
						

							
SPECIAL TOOLS
1-11
EAS20260
SPECIAL TOOLS
The following special tools are necessary for complete and accurate tune-up and assembly. Use 
only the appropriate special tools as this will help prevent damage caused by the use of inappropri-
ate tools or improvised techniques. Special tools, part numbers or both may differ depending on the 
country.
When placing an order, refer to the list provided below to avoid any mistakes.
NOTE:
 For U.S.A. and Canada, use part number starting with “YM-”, “YU-”, or “ACC-”.
 For others, use part number starting with “90890-”.
Tool name/Tool No. Illustration Reference 
pages
Piston pin puller set
90890-01304
Piston pin puller
YU-01304 5-71
Radiator cap tester
90890-01325
Radiator pressure tester
YU-24460-01 6-3
Radiator cap tester adapter
90890-01352
Radiator pressure tester adapter
YU-33984 6-3
Steering nut wrench
90890-01403
Spanner wrench
YU-33975 3-27, 4-59
Ring nut wrench
90890-01268
Spanner wrench
YU-01268 4-59
Damper rod holder
90890-01423
Damping rod holder
YM-01423 4-51, 4-52