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Servo Motor
- Thread starter jgrams
- Start date
On carbureted model: the servo will cycle once each time the engine is started. If the servo cycles three times and then quits, the cable lengths are incorrect and must be adjusted.
On EFI models: the servo will cycle once at 7100 RPM. If the servo cycles three times, cable length adjustment or valve inspection is required.
When the engine is first started (2004/2005 models), the exhaust valves will cycle once at low RPM (2500rpm) on all models except the Firecat 700 EFI and carburated models. On these models, they won't cycle until 7200 rpm.
The servo motor consists of two circuits. One circuit is a DC circuit, which operates the DC motor within the servo, and the other is a potentiometer, which measures the resistance, amperage, and servo pully position.
The computer within the CDI unit and ECU have been programmed to operate the servomotor between a low and high resistance range. If resistance is not within the range, the computer will shut down the APV circuit. The computer will then make a total of three more attempts to cycle the power valves. If the correct resistance, amperage, or pulley position isn't seen, the APV circuit is shut down and no more attempts will be made until the engine is shut down and restarted.
On EFI models: the servo will cycle once at 7100 RPM. If the servo cycles three times, cable length adjustment or valve inspection is required.
When the engine is first started (2004/2005 models), the exhaust valves will cycle once at low RPM (2500rpm) on all models except the Firecat 700 EFI and carburated models. On these models, they won't cycle until 7200 rpm.
The servo motor consists of two circuits. One circuit is a DC circuit, which operates the DC motor within the servo, and the other is a potentiometer, which measures the resistance, amperage, and servo pully position.
The computer within the CDI unit and ECU have been programmed to operate the servomotor between a low and high resistance range. If resistance is not within the range, the computer will shut down the APV circuit. The computer will then make a total of three more attempts to cycle the power valves. If the correct resistance, amperage, or pulley position isn't seen, the APV circuit is shut down and no more attempts will be made until the engine is shut down and restarted.