2003 300ex won't start HELP?

[broke300ex]

I am real handy with cars but I'm lost with ATV's... My son's 300ex began stalling while riding last year. It would run for hours and then just stop for no reason. 10 Minutes later it would start up and be fine. This went on for quite sometime.

Toward the end of last season it stalled as usual but this time it would not restart.

I have:

Replaced battery

Checked fuses under seat (okay)
Pulled Carb and sprayed starter fluid directly into intake port while cranking engine over(never fired even once)

Pulled spark plug and laid it on head. Turned over machine and saw a very small hit/miss spark. Very Very small spark, almost none!

Engine turns over fine no problems.
No mechanical noise when it stopped it just stopped firing (in my opinion) Like it ran out of gas

I have replaced the small round coil like part on the frame that the spark plug plugs into. (no results)

I jumped all the switches on the handle bars still with no results.

Can someone tell me what I need to check on this machine. My 13 year old son is so upset that I can't get this thing running.

Thanxs, Jim

[rooster300ex]

Maybe its the cdi box. Its on the right side under the front fender.

[broke300ex]

Is there any way to test that?

[cmanningjr]

Only way to test it is to put another one in it...

[mor300ex]

i had this problem with my 300 ex it ended up being a broken prong in a plug under the gas tank on the left side it had about six wires in in it it was a red wire that fed spark i pushed on the wire and it started then died so i just cut the wire and bypassed the plug after inspecting it and discovering that was the problem

[honda300EXtreme]

i would start by tracing all electrical connections and clean all connections and check for broken/ damaged wires,

try another cdi box, ( possible but not likley in my opinion, clean the carb out good,

check/ adjust valves if need be,

this is a start, and the most common and simple to fix solutions




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good luck