yesterday i was riding to an friend house and once i tried to start it when trying to leave it wouldn't make a sound.I have an switch where the key turner thing was.everything was turn on and i just started it atleast 5 to 20 min ago

 

get a multimeter, start checking voltage readings to/from battery, key switch, solenoid, starter, and so on. we'll help you find the problem. sounds like an incomplete circuit. wiring connections can become loose, disconnected, etc... during and after a ride due to vibrations or electrical issues/shorts. we'll help you find it.

harbor freight has cheap $4 meters that work great.

 

Thanks ill try this when i get back also my brake light dont work

 

pull the bulb and check it like a regular bulb. if you can put it somewhere to turn it on to check it, ok, that'll be fine. if not, do this: i've never messed with a 300ex, BUT, i got a 250EX. i can hear my brake switch engage up on right handlebar. sounds like a "tink". if you got that, then i'd say either your wiring going back there to the rear from the switch is bad(incomplete circuit/exposed wiring going to ground), or the bulb is burned out. good luck

 

to be honest with you, i don't know if the 300ex has a safety interlock for the brake switch or not,hmmmm......
but after you establish electricity, double check your neutral switch

 

okay i fixed the bike not starting ended up being the spark plug not properly plugged in however the backlight ill have to wait until im finished eating for

 

what do you mean by neutral switch

 

a 300ex is a 5 speed, right? well, you have neutral, right? do you have a gear display that shows "N" on the "dashboard"? if so, then you have a neutral switch. my 250ex does so the starter interlock will work, i was unsure about the 300ex. sorry if i've confused you.

 

its cool however the guy that i bought it from took the dashboard out but it does have neutral but how do the switch look like

 

well now that you ask, i'm gonna have to go look. depends on the quad. i better go look at mine. sorry about that....