Drop in voltage

[scobman]

Working with an original oem '71 xs1b

battery has a full charge, voltage drops to 7 when ignition switch turned on.

1. Bad voltage regulator ?
2. Faulty ignition switch ?
3. something else ?

 

[pamcopete]

sconman,

Take the battery down to a shop where they can load test it. Like, Advance auto. The test is free.

 

[scobman]

Battery tests out good, load test good.
I have a 2nd brand new battery, samething happening.
Replaced the volt regulator with a known good one, replaced ignition switch with brand new one, replaced left handlebar switch with brand new one.

Maybe the brand new mikesxs wireharness is faulty?
Dunno ?
feel like selling it as is, $4500

 

[XSLeo]

Try unhokking the regulator and try it. This will tell you if the rotor is shorted. Thats what it sounds like to me.
If the voltage holds, check the rotor ohms. 5 ohms between the slip rings, infinity from slip rings to the body of the rotor.
If yours is bad the ohms will be very low, like 1.8 ohms or less.
Leo

 

[daroberts3]

Does the headlight come on when you are taking this voltage reading?