[amritc]

Hi, In the alternator set up where you have 4 wires (12v), how much voltage should the orange/amber wire carry with the engine running. And is the yellow wire supposed to carry any current?

Using a tester light I can get the bulb to light up from the orange/amber wire but not from the yellow one. My headlight is not working and I can see that the AC headlight regulator does nto have any current flowing into it (tested it with a DVOM). Can I bypass the wiring harness and supply current to the AC regulator directly from the orange and yellow wires from the alternator? 

Thanks very much.

[High On Octane]

The alternator is phased, meaning each wire puts out different voltage depending on what RPM your engine is spinning.  And a test light isn't going to tell you anything other than if there is juice or not.  To properly test an alternator you need a descent multimeter.  Again, depending on engine speed, each wire should be roughly 60-80 volts, each activating at different RPMs.  To make sure your entire electrical system is working you should test voltage at the battery too.  Everything turned off, a healthy battery should hold between 12.4-12.9 volts.  Bike running with lights and everything on, at idle your voltage should be around 12.8-13.3 volts.  Engine speeds over 1800 RPMs you should be running right around 13.8-14.4 volts.  Anything less usually indicates a weak alternator, anything over that could be an indication of a failed rectifier/regulator.

Scottie

[amritc]

Thanks Scottie.

so the Yellow wire will put out some voltage at a certain speed but not at idle speed (unlike the orange wire which is putting voltage out at idle)?