The above link is to the drawing I made showing the entire 650 charging system that has the Mechanical Voltage Regulator or VR. (The Solid-State Voltage Regulator or SVR is discussed below.) Personally, I think one needs to learn WHAT the system is supposed to do before he can know WHY it isn't doing it. So if you want to learn, read on. NOTE: You might want to print it out and refer to it during the discussion.

Referring to the drawing..... When the ignition switch is turned on voltage from the battery flows through the switch along the brown wire into the VR, through the VR's switching contact out the green wire and over to the rotor coil. Then through and out of the rotor coil to the brush holder located on the stator where it along with the black wire attaches to the engine which is grounded back to the battery (Crows feet). NOTE: The black wire from the regulator is connecting the regulator's operating circuitry to ground at the rotor to assure accurate voltage readings during operation.

Now with the ignition switch on and said voltage applied to the rotor coil, a magnetic field forms around it. When you start the cycle the rotor and it's magnetic field rotates causing voltage to be produced in the three stator windings by aphenomenon called Electro Magnetic Induction. (Whew!! One of them fifty cent'rs.) This voltage is fed into the rectifier by the three white wires where it is changed to DC voltage. It leaves the rectifier through the red wire and goes straight to the battery, charging it. Notice (visualize) that with the ignition switch closed the red wire is connected to the brown wire and basically they are now one and the same. Therefore the voltage on the brown wire rises and falls at the same level the red wire voltage does.

Now lets go back to where the brown wire connects to the VR. When the voltage level at this terminal of the VR reaches 14 to 14.5 volts the magnetic coil to the right of the VR's contact switches the contact anddisconnects the green wire from the hot (Brown) wire and connects the green wire to ground (Crows feet). This action turns off the rotor coil and the magnetic field goes away. STAY WITH ME HERE NOW! With no rotor magnetic field, the stator does not produce charging voltage anymore. As a result the voltage on the red wire drops to what ever the battery voltage is. Since the brown wire is connected to the red wire (via the igi. switch) it's voltage level also drops to what ever the battery's voltage is. And if the battery's voltage falls below approximately 13.5 volts (the headlight ignition coils etc. will pull it down), the VR's magnetic coil no longer has enough strength to keep the VR's contact switched.

So... the contact changes back and connects the green wire to the brown wire, voltage is again applied to the rotor's coil, it begins producing voltage in the stator again. This voltage is again rectified and sent to the battery, and the above cycle repeats it's self over and over, in an oscillating manner continuouslymaintaining the system voltage at around 13.5 to 14.5 volts depending on the load.

Note: When in operation the mechanical regulator will seemingly chatter. This is normal since actually the VR's magnetic coil is rapidly turning on and off which in turn moves the VR's internal contact back and forth. Also note the Zig Zag line running from the Brown wire to the Green wire inside the VR. This is a suppression resistor to keep the VR's contact from arching while oscillations during operation. Additional Note: A lot of people ask about the Yellow wire coming off the stator. This goes to the safety relay. What does the safety relay do? Well, the yellow wire taps into the stator charging coils (White wires) and puts out a voltage telling the safety relay the motor is running and the alternator is producing voltage. It in turn disengages the starter circuit so's not to grind the starter gears and on some models it also turns on the headlight circuitry. Tests show the voltage on the yellow wire while the engine is running should be around 6 to 8 volts depending on engine rpm. The safety relay pulls in at around 4 volts. Also, based on it's operating voltage I don't think the safety relay's coil is designed to be connected to 12 volts, at least not long term. So bear this in mind.

OK.... Put voltage on the brown wire,.... get higher voltage out on the red. And the green turns the rotor on and off. Simple Huh?? Takes a little studying but you'll get it. So.... Now that we know WHAT it's supposed to do and if your having problems, let's see what,.no, WHY it isn't doing it's thing. For this refer to my Next Page "Troubleshooting Your Electrical".....

Solid State Voltage Regulator
The above link is to the drawing I made showing the entire Solid-State Voltage Regulator or SVR charging system for the 650. It's similar to the mechanical with a few exceptions. If you have one of these systems and want to know WHAT it does, read on. NOTE: You might want to print it out and refer to it during the discussion. Referring to the drawing.....

When the ignition switch is turned on voltage from the battery flows through the switch along the brown wire into the IC regulator section and also over to the rotor coil. Then out of the rotor coil along the green wire back into the SVR IC (intergrated Circuit) regulator section which connects the green wire to ground accordingly. When the ignition switch is turned on and said voltage is applied to the rotor coil a magnetic field forms around it. When you start the cycle the rotor and it's magnetic field rotates causing voltage to be produced in the three stator windings by a phenomenon called Electro Magnetic Induction. (Yep there it is, One of them fifty cent'rs.) This voltage is fed into the rectifier section of the SVR where it is changed to DC voltage. It leaves the rectifier section through the red wire and goes straight to the battery, charging it.

Notice (visualize) that with the ignition switch closed the red wire is connected to the brown wire and basically they are now one and the same. Therefore the voltage on the brown wire rises and falls at the same level the red wire voltage does.

Yep.... Put voltage on the brown wire,.... get higher voltage out on the red. And the green turns it on and off. Same as the mechanical one. Just as simple, Huh?? As I noted above, it takes a little studying but you'll get it. So...Now that we know WHAT it's supposed to do and if your having problems, let's see what ...no ... WHY it isn't doing it's thing. See Next Page..... Troubleshooting Your Charging System Special Note: To those familiar with electronics. The topics of transistor biasing, variable current and or rotor field weakening was not discussed in order to allow those not familiar with electrical/electronics to better understand how the system works. The end result is basically the same. The rotor field is controlled in such a manner as to control voltage output of the stator.