93 KX 250 No Fire

[jforbesautotech]

Ive got a 93 kx250 I just bought and when I bought the bike it had no fire on the plug. To make a long story short I have replaced the stator, cdi box, and the coil. I have checked voltage from the black wire with white stripe coming out of the cdi box and it shows voltage up to 14 or 15 volts depending on how hard you kick it, ok it shows that same voltage on the electrode coming out of the spark plug when you kick it but still no fire. Also something weird if you mount the coil on the frame it will not show voltage but if you let it dangle in the air it will show voltage but no fire. Any help would be much appreciated I am almost to the pull out my hair stage. Thanks

[DoldGuy]

J......,
Make sure the frame/engine combo has a good ground between them. I had a similar problem on my 93 kx125, tried the CDI, then the coil (from my 250,same part #) and the coil fixed the problem. I then ordered a new coil & thought the problem was fixed. Same problem persisted put 250 coil back on problem fixed!?!?!? A new coil does NOT come with the cap so removed from the old coil & installed. The resistor cap was opening when it warmed up & lost spark. The problem was getting progessively worse.
Remove the kill button wires, check for frame/engine ground, remove cap (coil wire straight to plug). We do not need to loose any hair over this as I have already done that. I hope the info helps, keep us posted.
DoldGuy

[jforbesautotech]

I checked the kill switch and it checks ok also unplugged it and get the same reading and the frame/engine ground seems to be fine. I am just wondering if I should be getting that much voltage out of the cdi I thought it was supposed to be low and then the coil made the high voltage. I dont know???

[DoldGuy]

I don't recall the out put voltage from the CDI, but it sounds as it will be something simple that we all can learn from. Are these "OEM New" parts you have installed? Have you removed the Cap? I just picked up a 93 KX 250 with extremly low hours (has been sitting since 1993 Southwick Nationals) & only has about 7 races on it that I can measure resistance on the components when I get a chance.

[jforbesautotech]

The stator is a moose racing stator I bought from the dealer and the cdi I got from ebay and it shows the same reading as the other one and the coil I got from the dealer. The cap is also new.

[BDI]

You could possibly have a bad harness 

[KX500freak]

i had a broken ignito-coil wire once ,i was also desperate seeking for the solution,
had it rewound and never any issues again .

[jforbesautotech]

Ok I have yet to figure this problem out since it is doing something I have never seen before. I dont understand why I am getting 17 to 18 volts at the end of the spark plug wire and even on the plug electrode but it still wont fire the plug. It wont show anything when I ground the coil but if I leave it hanging in the air I get voltage??

[DoldGuy]

JForbes,
Not to sound rude, but if you are getting voltage it HAS to have a ground SOMEWHERE. It sounds as you are lost in the forest, step away for a moment & think about your post. If you have voltage with the coil without it mounted where is it's Ground coming from? I think the answer will lead you to your resolution of the problem.

[Hillclimb#42]

Also, it sounds like to me 17 to 18 volts at the end of the plug wire is not what its supposed to be. I think its thousands of volts after going through the coil. Sometimes a kill switch can cause funky problems. have you tried disconnecting it?

[DoldGuy]

#42,
It is correct that amount of voltage is not enough to fire a plug ( My Beckman meter can't go that high ) his previous post states he was reading voltage from the CDI. The way simple folk check a Coil is by resistance & not by voltage (I did work at a shop in the 70's that had a tester that could check the voltage under load). As I posted previous, if he checks resistance & not voltage, I will try to help out with a comparison bike.

[DoldGuy]

Comparison Bike 

[Hillclimb#42]

She's a beaut'.  That's a slick '93, DoldGuy.

Is it possible that the wires are not color coded the same as OEM and throwing you off?

[jforbesautotech]

I did check resistance from the new and old coil the new one around 10 ohms and the old at 9 ohms. I dont have a manual so I am not sure what all of the readings are supposed to be though I do have one ordered. I have a 95 kx500 as well and was just checking what kind of voltage it was putting out and it is around the same thing. I just think I have got some wires crossed or something I am not exactly sure if the way its hooked up is the right way, I am just going by the way it was hooked up when I got it. Doldguy I would really appreciate it if maybe you could look at yours and see how the stator wires hook up to the cdi and also what readings you got from it. Thanks

[DoldGuy]

JForbes,
I will try to get some pics & post soon, and try to get the resistance readings later as am trying to get stuff ready to ride for this coming weekend (taking some newbys out so I can throw dirt on SOMEBODY ).