Basic electrical question

[97tiger885]

This is not for the Tiger, but here goes...I have an unidentified wire which needs to be hooked to the battery.  I don't know whether it goes to the pos or neg terminal.  The wiring diagram does not show it.  The wire runs under the gas tank.  Tracing it would requiring removing a lot of body work and the tank.  I would prefer not to do that.  How can I determine if this is a wire for power or a wire for ground?  

If a voltmeter is involved, I will need very, very specific instructions such as black here and red there.

[metalguru]

Personally I would trace the wire to find where it goes to be sure of correct connection or bonfire, that is even if it is not in use.
Just not worth any risk with electrics especially if it is un protected.
If it takes 30 mins to trace it and establish what it does or doesn't do, that is the time your bike will take to fully burn out with everything in close proximity. eeermmm now what side of the battery did you put that wire on?

[Rapier]

My voltmeter auto-corrects, i.e. if I hook the black to the hot it does not care.

With the bike turned off:
Clip the red voltmeter lead to the exposed wire, and the black to known ground (point on the frame).
If you get a reading in Volts (most digital will be reading some background mV) then you have a hot wire, direct connect to the battery most likely.
Assuming you get no change (hopefully) turn the power on on the bike. If you get a reading in V then this is a hot wire.
If there is no change then this is probably a grounded or disconnected wire. This also assumes there are no blown fuses.

If you do not have a Volt Meter, get a lightbulb (spare brake light) tape a wire from the bottom of the bulb to ground and touch the unknown wire to the side. Folloow the above procedure, the lightbulb is a simplified voltmeter. Incadesent lightbulbs are typically pos/neg irrelevant.

YMMV

Additional information:
http://www.aa1car.com/library/tselec.htm

[rybes]

personally im with metalguru. for me its to much of a chance to mess things up just for the sake of 30mins of time to remove the bodywork.
dont guess, look

[Yankee Dog]

Whats not working on the bike?  It is not entirely unknown for bikes to have extra wires not connected to anything. What makes you think this one has to be connected to the battery.

Yankee Dog

[97tiger885]

Personally I would trace the wire to find where it goes to be sure of correct connection or bonfire, that is even if it is not in use.
Just not worth any risk with electrics especially if it is un protected.
If it takes 30 mins to trace it and establish what it does or doesn't do, that is the time your bike will take to fully burn out with everything in close proximity. eeermmm now what side of the battery did you put that wire on?

Man...you guys are no fun at all.  I have always wanted to compare German smoke to English smoke.  Besides my workspace is a 100 year old wooden building with wood flooring.  No fire danger there.  

Turns out I took the tank and a whole lot of other stuff off to trace the wire.  Ends up it goes to the power plug.  The inline fuse should have been a clue.  

Thanks for the help.