Vboost Help

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yoshimasters

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Recently purchased a 2001 vmax used 20,000 miles. The Vboost does not work. When power is on, no movement to the v-boost, no noise or anything. Someone installed a toggle switch that leads to this black cap. The Cap is wired to the control unit and back to the first coil and to a wire cluster by the coil. Can anyone identify what this is? Also recommendation on what to test to trouble shoot the Vboost system?
 

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02GF74

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There are aftermarket devices that double the rpm signal so that the vboost starts at 3,000 rpm instead 6,000. The switch enables or disables it. My best guess is that is what has been fitted.

The device could be at fault so as FM says, remove it to run vboost as yamaha intended.

If vboost still fails, then disconnect the circular plug and by applying power to 2 of the pins, the motor to move the valve can be tested. (I'll need to look up the plug pinout)

If it works, then providing there is power and rpm signal to the vboost unit, the unit itself is faulty.

Very commonly the soldered contacts inside the vboost fail and often pressing on different points of the case can get it to work, albeit temporarily, as the circuit board flexes to remake the contact. Once this has been confirmed, the circuit board needs to be removed, the failed connection located and resoldered.

Note that you can do the pressing test right now before removing anything.
 

yoshimasters

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Thanks for the quick replies and wire diagram. Ill return it to stock and proceed with your recommendations.
 

Parminio

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Fire-medic

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An easy fix, glad you worked through it and provided feedback on the success.
 
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