2008 YAMAHA YZ450F check engine

[x] Cancel search: check engine

Page 173 of 188

YAMAHA YZ450F 2008  Owners Manual 6-3
IGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the ignition coil from 
spark plug.
2. Remove the ignition coil cap.
3. Connect the dynamic spark tester 
"1" (ignition checker "2") as 
shown.
• Ign

Page 176 of 188

YAMAHA YZ450F 2008  Owners Manual 6-6
THROTTLE POSITION SENSOR SYSTEM
HANDLING NOTE
Do not loosen the screw (throttle 
position sensor) "1" except when 
changing the throttle position sen-
sor due to failure because it will 
cause a d

Page 177 of 188

YAMAHA YZ450F 2008  Owners Manual 6-7
THROTTLE POSITION SENSOR SYSTEM
10. Put the aligning marks "a" on the 
throttle position sensor and car-
buretor.
11. Stop the engine.
12. Remove the carburetor.
13. Tighten:
• Screw (throttle p

Page 178 of 188

YAMAHA YZ450F 2008  Owners Manual 7-1
ENGINE
TUNING
ENGINE
CARBURETOR SETTING
• The air/fuel mixture will vary de-
pending on atmospheric conditions. 
Therefore, it is necessary to take 
into consideration the air pressure, 
ambient

Page 181 of 188

YAMAHA YZ450F 2008  Owners Manual 7-4
ENGINE
SPECIFICATIONS OF JET NEEDLE
EXAMPLES OF CARBURETOR SETTING DEPENDING ON SYMPTOMDiameter of straight portion
RichLean
NPQRS TU
Rich 1 richer NFLN-4 NFLP-4 NFLQ-4 NFLR-4 NFLS-4 NFLT-4 NFLU-4

Page 182 of 188

YAMAHA YZ450F 2008  Owners Manual 7-5
ENGINE
* This should be taken simply for an example. It is necessary to set the carburetor while checking the operating conditions 
of the engine.
Page:   < prev 1-10 ... 9-16 17-24 25-32 33-40