Yamaha MX775 - CHECKING THE RECTIFIER;REGULATOR; CHECKING THE FUEL INJECTORS

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ELECTRICAL
ELECTRICAL COMPONENTS
CHECKING THE RECTIFIER/REGULATOR
1. Check:
• Rectifier/regulator output voltage
Out of specification  Replace the rectifier/regula-
tor.
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a. Connect FI Diagnostic Tool.
b. Connect the digital circuit tester (DC) to the rectifier/
regulator harness.
c. Start the engine.
d. Measure the regulated voltage.
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CHECKING THE FUEL INJECTORS
The following procedure applies to all of the fuel injectors.
1. Remove:
• Fuel injector
(Refer to “FUEL INJECTORS AND INTAKE MANI-
FOLD” on page 4-9)
2. Check:
• Fuel injector resistance
Out of specification  Replace the fuel injector.
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a. Disconnect the fuel injector coupler from the fuel
injector.
b. Connect the digital circuit tester () to the fuel
injector coupler as shown.
Regulated voltage:
14–15 V
FI Diagnostic Tool:
90890-03253
Model 88 Multimeter with tachometer:
YU-A1927
• Positive tester probe 
Red (wire harness color)
• Negative tester probe 
Black (wire harness color)
Resistance:
11.4–12.6 