So my 04 is dead

[SMPKX500]

Took out my 04 K5 Thanksgiving weekend and after a quick warm up the bike started stalling. At first thought it was fuel but quickly ruled that out.
Changed out the plug with no luck. Kind of think its the CDI unit but I'm not sure. The coil could be going as well.
Anyone know how to test the box? Who has them for a good price? I remember replacing one on my 250 once, wasn't cheap.

[KX500freak]

what color has the spark?
how bright ?


about testing ,it can be done i think,dunno how exact
but you don,t have a buddy with a kawa ,then you could try his cdi first

[SMPKX500]

Well I kicked it over with the plug out grounded and got no spark. But then when I put it back in it started for a minute.
That's to problem. It will run for a minute maybe two but then it just shuts off.

[KX500freak]

hmmm sounds also a bit like to rich jetted,
what jetting do you run ?
what mix ? 1:40 is my mix
does it stall whatever revs you,r making?
or just above idle?
anyway check the plugcable too ,maybe loosend a bit .
and what plug brand /type ?
some plugs can fool quite fast if jetting is off
i have denso and twinspark and jetting okay ,never fools plugs

[SMPKX500]

Its not a spark plug issue. And I have never fouled a plug. I run a NGK BR8EG. Stock jetting. Sometimes it will start, run perfect then just die. I think its the CDI unit. If it were the coil it wouldn't be intermittent.
Are the CDI the same though the years or do they change?

[Johnniespeed]

If you are sure the problem is ignition related, and the key is not sheared in the crank, you could send me your CDI and I would install it on my 04 K5 take a little ride and send you back your CDI.
  I have a co-worker with a Banshee and no spark, after a new CDI and a new stator he found the kill switch was shorted out. Very expensive guess work.
  I have a CDI tester for a cr250, it consists of a known good stator,known good rotor, known good CDI,known good coil all assembled with a hand crank to spin it. I can simply place a suspect part in the tester and spin it while watching its spark plug . I have not yet made one for a KX500, but maybe someone on this site has made one.
  John

[SMPKX500]

First thing I did was disconnect the kill switch to rule it out. I haven't checked the pin yet so that will be next. I thought about buying a monster coil to see if its that but anytime I ever had a coil go bad it never was intermittent. It worked or it didn't. If I cant get it going maybe I will mail it to you. I had one go out on my 250 and It was pricey.

[KX500freak]

Its not a spark plug issue. And I have never fouled a plug. I run a NGK BR8EG. Stock jetting. Sometimes it will start, run perfect then just die. I think its the CDI unit. If it were the coil it wouldn't be intermittent.
Are the CDI the same though the years or do they change?

okay ,still i do not like the ngk brand ,one too many failures..
and for the cdi  you can take any cdi from a kaw500 /250 2stroke as far as i know ,for a test ride
goodluck

[don46]

Not sure what year you have, but 90-04 are the same and 86-89 are the same CDI box. I don't know about older 250's but the newer ones are different and won't work. I've seen stators go bad, but haven't had a CDI fail, of course they do fail. Your right on the coil they rarely fail, you could use a 250 coil for testing, they may be a bit different in design but will work fine provided you ground it properly. Make suer you have checked the flywheel key to ensure it hasn't sheared.

[apple]

I`ve had the same exact problem 2 times, spark coming and going and the bike dying in the d**ndest places like far far from the car. As for the kill switch, if it`s like my 2000 you have to jumper the switch, not just disconnect it to get spark. Mine was giving me fits before I found out it was the problem. Another time the bike just lost spark and wouldn`t start and then got the spark back for 6 rides then went away again. I cleaned up the ignition ground wire that bolts right onto the ignition coil mount bolt. Since I cleaned that connection up I haven`t had a problem and that was last year. Hope that helps.

Jack

[SMPKX500]

Well got back to it after letting it set for awhile. Pulled the carburetor and reed cage only to find the ends of my reed pedals damaged. I thought that might be the problem so I  installed the V-Force.
 First kick it came to life and I thought it was good until it stalled again. I guess the coil will be next. Runs fine until it warms and then stalls with no restart. This bike is pissing me off!

[stroke.n.smoke]

That does sound like a coil, but make sure you check all the conections under the tank going to the coil.  I had a problem similar to you and it was just a loose connection under the tank, they all looked like they were clipped together but one was just resting in the cover and would hit and miss once and a while.  took me a while to figure it out but was a matter of pluggin in the wire.

Good Luck...

[KXcam22]

Also keep in mind that the ignition pulse trigger can also cause problems as it encounters heat and/or vibration.  I have only seen this on Yamahas but it could happen to any brand. The good thing is that once it completely dies you can test for it with an ohm meter. Cam.

[DoldGuy]

SMP,

I had a like problem: KX125 ran great until it got warm (approx 10-15 min.) and then would just die (pulled the plug, damp with fuel) let the bike cool down for a couple minutes and would start up and repeat the whole process. Checked the stator and coil with a meter (checked OK), borrowed a CDI thinking this would surely be the fix, and the problem still persisted. Removed the coil from my 250 (same part #) and installed, the problem was fixed. Ordered a new coil, installed it, went to the race track, problem was still there. Pulled the 250 coil again and installed problem fixed.

Bottom Line: It was a bad Plug Cap (Resistor Cap/When it would get Hot it would Open and loose contact). New coil did NOT come with a cap, removed the cap from the old coil and installed. Try removing the plug cap and run the coil wire direct to the plug.

I hope the solution tp the problem is simple as this! (keep us posted)