Fuse on main ing box

What all does that fused supply B+ voltage too ? Do you know ? That would be your first thing to find out ! Do you know what a electrical distribution diagram is ? Do you know how to test electrical circuits with a DVOM - digital volt ohm meter ? Do you know what a short to ground is ?
Which fuse ? IGN A - 40 amp ,under hood fuse / relay box ? This fuse powers the Starter Relay and Ignition and Start Switch
Does your vehicle have a manual or automatic transmission ? The starter relay could be shorted inside , It's also located in the under hood fuse box . If you pull the relay out of the box it's plugged into an look on the bottom of it you would see four sets of numbers ! 30 & 87 an 85 & 86 . If you were to jump 30 to 87 in the relay box the starter should spin the engine over , not start an run just spin ! 85 & 86 is the control side . Could be the ignition switch !
That 40amp fuse powers a lot of subsystems !

Here is a web site for free diagrams !
http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model an engine , Under system click on electrical distribution , under sub system click on power distribution . Then click the search button .Click blue links one at a time . First blue link scroll down to the second diagram . You will see Ign A 40 amp fuse at the top of the page .you will also see it powers the igintion switch ,look at last part of ignition switch , when in start or run that 40 amp fuse powers all those other fuse's plus three relays i see there also . A/C compressor relay , rear window defroster relay ,daytime running lights . Any one of those circuits could have your short . You need to isolate the circuits , pull fuse's till the fuse doesn't blow !

Main fuse, not in fuse box, near starter relay.

30 amp may be too high, could have fri\ied wire\ing anywhere, Good luck.

Hard to say without make, year, and model-but check all fuses in the power distribution box under the hood- ignition, alternator fuse, etc.-all of them, the small ones and the maxi-fuses. All fuses are pretty cheap. If you still have nothing, you may need a wiring diagram to check for fusible links that would be power distributors right off or near the battery. Fusible links work much like a fuse, and most have been replaced by maxi-fuses, but many vehicles have both. If there is a designated main fuse, it should be in the distribution block or box under the hood.

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.

It is OK to jump start your motorcycle from a car battery as long as you do not crank the starter too long (it will burn the armature) and as long as the car/other vehicle is not running when you jump start your bike ( you can damage your electrical components( igniter box)). See if you can exchange one with a friend to see if that is the bad component.

The main fuse (30 amp) is on the starter relay under the red plug with the thinner wires going into it.

If there still is no response to your ignition switch once that you already have check the fuse in the starter solenoid of your bike then you have to service the ignition system. but if you can't then you have to go to a mechanic. The mechanic should check the ignition switch , the ignition coil ,the starter solenoid, the spark plug ,the spark plug cable , then the battery. if there is a malfunctioning or worn out of these said parts then you have to repair it or replace it. then you also have to check the wires if there are loose wires or worn out wires then reconnect if loose wires but if worn out then replace the wires.the most important for some times is the fuse if there i a worn out fuse you have to replace the worn out fuse. But if the fuse you replace cant hold the wat/amp of the bike then place fuse that is higher than the former fuse you place.

It sounds as if the switch itself has a short circuit in it. First replace the fuse and pull the connector off the back of the switch and jump across the two large red wire connectors and see if it starts..