My bike shorts out randomly and blows the main 30 A fuse between the battery and the fuse box. I believe there may be a bare wire shorting to the frame somewhere, and possibly a wrong fuse in the fuse box. All the fuses inside the fuse box are 10 A except one that is 30 A. I'm not sure the 30 A one belongs in there, which may be linked to why the main fuse is breaking.

Thanks for the details, they do help. Is there a way you can disconnect different electrical circuits from the battery? Like Disconnect the lights, horn, or other components then start adding them back until you find the circuit or group of wires that causes the short. Because it seems you have a short somewhere, or something really putting a load on that 30 Amp fuse. So I'd break the circuits down to smaller pieces so that when you reconnect the lights, or starter, or whatever....that the fuse pops and you know the circuit causing the issue. You may have to open engine components like a magneto to isolate the circuits. But it shouldn't cost you anything except time.

You have a dead short . Disconnect the battery , set your volt meter to read ohms and send a current from each position on the ignition switch to the fuse block where the fuse is blowing . You should be able to trace the problem quite quickly .

sounds like the starter is shorted out or the bike was tried to start when battery was near dead and the starter is engagaed if starter is engagaed put it in gear and bump(push the bike ) it a few times forward and back this should disengage the starter if it still blows fuses the you may have a shorted windings in the starter and it will need to be rebuilt

Low battery will not blow a fuse. If it blows right away when you turn on the ignition you have a main electrical short. Disconnect the regulator to the battery connector at the regulator to see if you have a shorted regulator. After the main fuse blows you should not have a battery drain so figure out also why your battery is discharged. Is your batttery no good. This would not blow a fuse in any case. Was the battery out recently, or disconnected. Make sure it is installed correctly and none of the wires are connected incorrectly. THEN you will have to start tracing the wiring from the main fuse to find the short circut.

Usually a bad regulator will only cause problems with charging...
Sounds like you've got a short somewhere in the wiring...I'd start by checking the ignition switch wiring and the connections going into the fuse box.

Yes, I've seen complete meltdowns of the entire wiring harnesses before. You're lucky you just blew a fuse. Now you've been given a warning that something is wrong and that you need to locate the problem. I've seen some older bikes that didn't have a fuse or circuit breaker in the wiring harness actually catch on fire because of a short.

Now, depending on what make and model of your bike is, determnes where you need to look. I work mostly on Harley's as that's what I've been working with since 1966. I find Harley's simplier to work on as they don't change as often as the Japanese bikes do. If your bike has a fuse box and it's not blowing any fuses other than the main fuse, the problem is most likely between the battery and that main fuse box. You really need to find a schematic of the wiring on your bike. Good Luck!

you have a short somewhere. check all the wiring tosee if any of them have bare spots(exposed wire) or if one the battery cables is toutching the frame.

Sounds like it is a short. Start checking all your main wiring and make sure that nothing has rubbed showing bear wire and that nothing is grounded on your system. The short in the loom if VERY common due to vibrations