Closed Throttle Position Detection System - Honda TRX450R Service Manual

IGNITION SYSTEM (After '05)
Adjust the throttle position sensor position so the
resistance between the terminals (Light green -
Green/yellow) is calculated, and tighten the screw to
the specified torque.
TORQUE: 3.4 N m (0.3 kgfm, 2.5 Ibfft)
Install the removed parts in the reverse order of
removal.
CLOSED THROTTLE POSITION
DETECTION SYSTEM
OUTLINE (OPERATING PRINCIPLE)
The closed throttle position detection system is an
ignition cut-off system that will prevent the engine
from running at any speed beyond idle while the
throttle lever is fully closed.
Both the throttle lever and carburetor throttle drum
have a position switch to detect their fully closed
position.
If the throttle drum "sticks" in an open position (car-
buretor switch OFF) and the throttle lever is fully
closed (throttle lever switch OFF) the ICM will cut off
the ignition to prevent engine damage or an acci-
dent.
Based upon the throttle lever and the throttle drum
positions, and their corresponding switch status,
the ICM will stop the engine from running (see fol-
lowing chart).
Throttle Lever
Position
Closed
Open
Closed
Open
Throttle Lever
Switch Status
OFF
ON
OFF
ON
Throttle Drum
Position
Open
Open
Closed
Closed
Carburetor
Switch Status
OFF
OFF
ON
ON
Ignition Status
OFF (fail mode)
ON (cruise, accelerate)
ON (starting, idle)
ON (initial takeup of throttle
lever free play)
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