My first thought was that the spring which holds the starter relay contacts open had failed, allowing them to close and supply power to the starter. But that would not explain why pulling the fuse wiring would stop it. At the least, this shows you your battery is in good shape.

R.F.  have you done any mods to the bike recently?  If so I would start with any wiring in around there or related to anything you've done  

Is there a test for the decomp controller?  Looking at the wiring diagram, it seems like a short in the decomp controller would activate the starter relay, and be stoppable by pulling the 20A fuse.   So maybe the decomp controller is going flaky, or the wires to it are touching somewhere.

The decomp controller requires the TINiest of inputs ( in terms of amps) to fire the starter. There is a single red ( 12 V) wire that runs near it. There is a wire on the decomp timer that, when given 12 volts, will fire the decompression solenoid & fire the starter. It will do it with the bike in gear, bypassing all safeties & even if the key is in your pocket,
I have a switch out of a DVD player wired in, strapped under the frame under my right thigh, if I ever have a starting problem, I can know a lot real quick by just touching that switch. I wanna say theres yellow on that wire, not sure now, I know its toward the front of the bike & I wanna say its second from the left in the connector. Anyway, the switch is Tiny, it would sit on my little finger nail. It carries no current to speak of, so, it wouldnt take much of a Skint Spot on insulation to allow a connection big enough to do what happened.
It Would take a near miracle to have the bike fall over & land 12 V on that wire & it stay there,, Wadda strange event that was,,

Some kinda "shoe" under the sidestand mite be in order,.
OR,, did it fall over first? Was it in gear & engine spin & it walk off the kickstand? Did the kickstand sink in the ground?

Well the ghost is back, and I know for a fact it's not one of my kids.  I witnessed it myself this time.  I had just let the dog out and shortly after that while I was standing there the starter just up and started churning the motor over    This just happened about 10 mins ago.  A sharp smack to the fender support stopped it, but for now I just pulled the pos wire from the battery till I can figure out what the heck it going on here.

R.F.

Then it's probably like Drums said...a short in the solenoid...plus after you rapped on the fender it stopped...I'm terrible at electrics but that's where I'd start.

SaVaGeEaRL wrote on 08/04/12 at 01:14:17:

Well it still may end up being that and something else,  but unless I'm reading the wiring diagrams wrong, the controller doesn't get any voltage unless the key is in the on position, so wouldn't this mean my key switch would also have a short in it as well, or a short in it's harness?  The way I read it is, there are only 2 places that have constant power and that is the large cable lead to the starter relay from the battery, and also the smaller wire lead to the key switch unless I'm missing something.

R.F.