I ride a Yamaha V-Star 1100. A few weeks ago I pulled into a parking lot and my motorcycle shut down. I mean completely! The engine quit and all the electrical turned off. There were no faintly glowing lights, the starter didn't click desperately as with a weak battery; it was simply dead.
I left it in the pub parking lot, figured out where I could borrow a trailer, and I brought it home the next day. The main fuse is under the seat, and once I took the bike apart that far I saw that it was blown. "Cool," I thought. If it was a transient spike or an old fuse, perhaps a fifty cent part would get my bike running again. As I put in a replacement *ZAP*! The fuse blew out instantly.
I did lots of tests with a voltmeter and found that the line that led from the postive terminal on the battery was shorted to ground. That's pretty much the simple recipe for a blown 30A fuse, but where was the short? I took the gas tank off the bike and tried to follow the wiring throughout the bike. The wires are all bundled and bound with electrical tape, so following a wire is nigh impossible. I found a wire the same gauge and color code that went to the main ignition switch. "Aha! Perhaps the switch is broken!" Further tests revealed that was not the problem, and I set about the tedious task of carefully cutting open the bundled wires.
I found the wire that led from the fuse went down, not towards the front of the bike and the ignition switch as I had assumed. I pulled off a side panel and found the voltage regulator. This time, I was on to something! I pulled it and sure enough, the power and ground pins were shorted inside the sealed unit. I called around, no one had one locally, so I ordered one online. It came in Friday and I installed it right away! After putting the tank back on, reattaching the many disconnected cables, replacing the battery, and bolting on the mufflers, it fired right up!
It was rewarding to have fixed it myself! Not to mention I saved a fair chunk of change in the process.