my 2000 300ex will not start! checked and doubled checked everything!! and the plug is fouling, any help is greatly needed

 

This is probably a dumb question, but, did you try a new plug? Check the airbox, maybe a mouse filled it full of stuff??? And last but not least, is the kill switch on the left handlebar on? Don't laugh, i've done this too.

 

LETITSNOW HAS A POINT. THINK ABOUT THE DUMB THINGS BEFORE YOU THINK ABOUT THE BIG THINGS. I'VE WENT ABOUT AN HOUR TRYIN TO START MINE AND THEN I FINALLY FIGURED OUT I DIDNT HAVE THE GAS TURNED ON. TRY IT, IT MIGHT HELP.

'98 300EX: DG EXAUST, BIGGER HEADER, AFTERMARKET AIR FILTER, PRO DESIGN KILL SWITCH, BRAND NEW HOLESHOT XCT'S, AND A WHOLE NEW BACK END.

 

You DID check the kill switch, right? (Sorta kidding, but: been there, done that.)

With spark (and clean plug; wash it off with gasoline at least), compression, and gas (preferably dry, fresh gas; at least, drain the carburetor float bowl through the dump tube and re-fill it), oughta start! Give it a whiff of starting fluid!

Still won't start? Even with jumper cables to a car battery? Then, start your trouble-shooting check-list countdown.

Good luck.

Diogenes