300ex Will Not Start!!!!!!!!

[Cody_300ex]

Ok guys I went outside to warm up my 300 to park it in the front yard beside my for sale sign for it. I started it up and turned up the idle while so it could warm up. Well all of a sudden its just shuts off, i thinking oh $hit i just seized it. I try to start it and it turns over, but will not start running for nothing. Tryed it with the lid on and off still nothing, tryed with the Choke off, half way, and fully on, still nothing. it was running the best it had ever run Monday. I just dont get it!!! :mad:

Has plenty of oil.

Its getting a good spark.

Has gas.

It was not on reserve.

Choke was off.

Air filter was just cleaned and oiled

The gas in it is Good.

[zephead400ex]

New plug?

[300exOH]

I'd check all connections and fuses. If that doesn't work check the plug.

[94snake300ex]

check the 15 amp fuse in the main power supply just inside the frame in front of the airbox then check all connections and for exposed wires then the plug.

ya i have a 94 trx300ex with:
bored .040 over
wiseco domed race piston
oversized black diamond valves
titanium r&d valve springs
ex. and intake. ported to the max
wb mid.range race cam
supertrapp e.a.r. exaust with 12 disks
oversized header
renthal sprockets 1 bigger fr and rear
ek supersport x ring chain
braking vented brake disk and pads
lsr machined dual carrier
pure sports bandit AT's all around on stock rims
uni filter and no airbox lid
ac nerfs
maier rear white race plastic
race cut red stock front plastic
and cr125 oneal bars

[Towlieee]

are you sure you haven't flooded it?

woulden't turning the idle up allow more gas and not more air to flow in?..

If thats the case you shoulden't need it choked + higher idle..

My friends 02 300ex, we leave the idle screw really low (at hot settings) so starting we have to choke it and leave it almost full choked for a couple minutes, but we never turn the idle up..

Before when his idle was up we just didn't choke it.. I don't think you need to choke + turn idle up, just dumping assloads of gas and little air

[miken]

It doesn't want to be sold!

Clean the plug, twist the throttle once (its a pumper carb), full choke if it has original pilot jet, crank. It should at least sputter. Do not touch the throttle if it starts, mine likes to die if I try to rush the warm up.
Mike -

[Iamgone]

Try checkin the kill switch, if mine is not right in the center or gets bumped off center it will not start. :eek:

[MichaelS693]

sounds like it was flooded or jetting is off;) :p :huh

[nj300exr]

befo messing with carb or anything, simply, check the fuses that everyone else said, and check the battery, maybe even hook it up to a booster with a 40 amp charge and real quick try to carnk it, dont leave it on 40amp for long tho, it will kill your battery, beileve me, ive jumped to conclusions thinkin it was the kill switch and carb and choke and all kinds of shizzle where all it was in the first place was the battery was dead.

[Cody_300ex]

No its turning over it just dont want to start. Jetting is spot on, it's not flooded.

[exrider360]

i am saying it is definetly the fuse the same thing happined to mine once beofre.

[400exdad]

Definately check the plug... especially if you haven't really ridden it in a while, but have started it up and let it idle a lot.

[jason4282002]

when my fuse blew mine wouldnt turnover

[kyleschonert]

have u tried push startin it? If its ne thing to do with electronics, push startin it should make it start.

[2muchquad]

i hate to be the bearer of bad news but you could have a bad crank.what gave it away was you said"it ran the best it ever did the other day"well EVERYtime that has happened to me or buddies,it was the bottom end going south.you said you thought you seized it after you started to let it warm up,why would you think that when it might have just stalled?because the sound was definately an alarming one even though it isnt locked.my yzf moto x bike did the same thing,it was the rod.it would still start but would just stop running and restart if it felt like it or i begged.hopefully i am wrong though.good luck:)