Motorcycle Repair: My GS450 blown fuse, suzuki gs 450, light dims

Question
I have a 1981 Suzuki GS 450, and I am working on it currently, so since it isn't being ridden yet, I don't have a battery, since it would just sit there, so when ever I wanna start it, I hook up the battery cables to my car battery, via jumper cables.  now up until recently it would work, but the last time I tried, it blew the fuse.  Now it blew the fuse as soon as i turned the key on.  So I never even got a chance to turn it on or anything.  It used to just start right up, or at least turn on.  now it just keeps blowing fuses and blowing fuses.  I also had recently put some different handle bars on it, so could there maybe be a pinched wire somewhere, and also, since it blow as soon as I turn it on, I have found that that means that it has something to do with the "hot wires" or something like that.  do you think you could tell me also which wires are hot ones?  Im not sure of all of them.  So my second question is what is making the fuses blow...  thank you

Answer
Clint,

I don't recommend using your car battery
as they have way too much current
for motorcyles. It is likely you have
a dead short on a battery positive or "hot" wire, maybe
a wire got pinched in the handlebar
change.

The main "hot" wire is the red
wire going to the ignition switch.
The orange and brown wires are usually hot too.
Other wires can be hot depending on
what switch is on or off.

Here is what you do, get a test light
or make one with an old 12 volt bulb.
Connect this across where your fuse
would normally be. Leave the fuse out.
Now when you turn on the key, the light
will come on brightly.

Try disconnecting the handlebar connectors
and/or other electrical parts of the bike
one at a time and see if the light
dims or goes out. If it does this is
the place to look for a bad wire or
a shorted wire (touching ground or the frame,
which is a negative battery connection)

You do not want any of these "hot"
wires touching another wire
or the frame of the bike anywhere.

You may notice the wire is warm or damaged
by heat. I suggest using a battery charger
or such instead of the car battery for testing.

The fuse will stop blowing when you find
the damaged wire, it could even be
in one of the handlebar switches
or ignition switch.
The fuse can only handle 15 amps of battery current.
When the "hot" wire is shorted to ground all of the battery's
current flows through the fuse overheating it and it blows.
This is a good thing otherwise it would be your bikes
wires burning up instead of the fuse.