It sounds like you know what you are doing. And yes, VERY basically the power valve raises the height of the exhaust port as the revs increase.
I will just list some of the basics here, which I suspect you already know. But you have to start somewhere.
1) Does the battery have a good charge? About 12.4 volts or more. Note that a single lead-acid cell gives off 2.1 volts. So 6 of them in series should give off 12.6 volts.
2) Is the drive motor stalling out due to too much mechanical resistance?
...Are the power valve cables adjusted up too tight? Maybe just slacken them a bit if they are.
...Are the power valves easy to turn by hand when not connected to the cables?
3) When you turn the ignition key on:
If powervalve is not in the "low" position, and engine kill switch is set to "Run", then powervalves will rotate to "Low" position.
However, if the TPS wires from carbies are disconnected, and engine kill switch is set to "Run", then the powervalves will rotate to "Hi" position.
I suspect that 3) above will be the stumbling point which probably points to the PV motor drive electronics in the PGM being stuffed, or the powervalve drive motor being stuffed, assuming all your electrical connections are fine.
If you disconnect the cables from the power valve drive pulley and apply 12 volts to the correct wires, (I think White and White/Black [any polarity]) you should be able to see if the power valve motor works or not as it will start spinning. Note that I haven't actually tried this myself, so don't trust me. It may be that you need to put a resistor in series with the power valve motor so as not to supply too much current to the power valve motor, if connecting it straight to your bikes battery.
Last edited by TuckerBag on Sat Apr 21, 2012 10:31 pm; edited 2 times in total