It could be due to a bad kill switch button. If you've some knowledge, unscrew the kill switch on your handlebar and check if the wires are not broken. If it's broken, you need to replace your kill switch. (Join both wires to bypass Kill Switch temporarily)
Other reasons, such as a Dirty spark plug, bad starter, corroded battery terminals, bad grounding, clogged fuel line, clogged air filter, dirty carburetor, etc., could lead to starting problems.
No. You should never do this. The ignition switch wires are too thin, and high power can melt them.
In fact, you should never bypass the motorcycle fuse. Let the fuse melt first before any major circuit damage.