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03 250sx not getting spark

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Started happening during the last ride...thought I fouled a plug, but that wasn't it. If I pulled the cap off and messed around with it a little bit, let the bike sit I could get it to start....but now I get nothing.

The bike was not wanting to start once I shut it down, got lucky a couple times and it started but on the last ride(because of this) had to walk it back to camp

Anything easy to check out?

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Check the spark plug boot. I've seen poor connections there. If that is not an issue check your grounds. Make sure you are connecting to bare metal. Then check every connection back to the stator. Pull the connectors apart and inspect them. Clean if you can, if you find nasty stuff replace as needed.

There are a lot of things it could be but those are the easiest to check and fix. The coil, CDI, and stator could be suspect. If after checking the above items your still having an issue you can try swapping the coil, CDI, and stator one at a time with another bike. You will find it.

Oh ya, check that kill switch,, it may be grounding out your bike killing the spark. You can simply disconnect it to test.

Have you pulled off your stator cover and looked?

Joe........

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Also.... I thought I had the same issue.. I replaced my handlebars and after re assembly it wouldnt start. Kicking, kicking and kicking and not starting. Turns out that I had somehow pulled my throttle cable out to far and it snagged. With the throttle in WOT it just wouldnt turn over.

Try this... pull the spark plug out of the engine and reinstall the wire on the plug with the plug resting on the engine. Kick start your bike a few times to see if you can see a spark... Thats what I did and sure enough... the spark was actually there.

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Also.... I thought I had the same issue.. I replaced my handlebars and after re assembly it wouldnt start. Kicking, kicking and kicking and not starting. Turns out that I had somehow pulled my throttle cable out to far and it snagged. With the throttle in WOT it just wouldnt turn over.

Try this... pull the spark plug out of the engine and reinstall the wire on the plug with the plug resting on the engine. Kick start your bike a few times to see if you can see a spark... Thats what I did and sure enough... the spark was actually there.

Yeah...with the plug out of the engine and me kicking there's no spark

Ive pulled off the stator cover but im not real sure what im looking at? I talked to a guy at the local dealer and he said it could be the thing coming out of that cover(where the wires are coming out of the engine, i forgot what he called it).

Gonna mess with it today, see if i can disconnect the killswitch and try that. Will go over all connections and check them out

Thanks

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Instantaneously no spark usually equates to one of four things;

bad/loose cable

bad spark plug

bad stator unit

bad CDI

From my experience, the cable that leads from the coil to the plug, is the root of many problems. That cable actually twists into the coil, so the first thing I'd do is unscrew it, cut 5mm of material off the end and screw it back in, then try.

If that doesn't work, take a multimeter and stick it to the input of the coil and see if you have the 100+ volts necessary for the coil to work. That will tell you the CDI and coil are probably good.

I doubt its a stator unit, it seems to me that its rare those fail unless they get over-heated or corrupt with water.

I'd also unplug and re plug in all the connectors and cables. I mean, you've got the big main CDI plug, you've got the coil plug, you've got the kill switch and the connector leading to the stator. Those and your ground, are the only things you need to make the bike start.

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I couldn't figure it out this weekend....went over all the connections and they were good. I'll try the thing with the cable that goes from the coil to the plug

Thanks for the input

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Instantaneously no spark usually equates to one of four things;

bad/loose cable

bad spark plug

bad stator unit

bad CDI

From my experience, the cable that leads from the coil to the plug, is the root of many problems. That cable actually twists into the coil, so the first thing I'd do is unscrew it, cut 5mm of material off the end and screw it back in, then try.

If that doesn't work, take a multimeter and stick it to the input of the coil and see if you have the 100+ volts necessary for the coil to work. That will tell you the CDI and coil are probably good.

I doubt its a stator unit, it seems to me that its rare those fail unless they get over-heated or corrupt with water.

I'd also unplug and re plug in all the connectors and cables. I mean, you've got the big main CDI plug, you've got the coil plug, you've got the kill switch and the connector leading to the stator. Those and your ground, are the only things you need to make the bike start.

I'm a noob so bear with me....you have the spark plug cap, and a cable coming off of that. take off the cap and trim a little off the cable on the side the cap connects to?

When checking with a dmm....take the reading from the spark plug cap itself?

The CDI is where?

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I was having the same problem with my 525. I replaced the cap with a Honda one but that didn’t fix it. It was the CDI.

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I was having the same problem with my 525. I replaced the cap with a Honda one but that didn’t fix it. It was the CDI.

that's what I'm thiking...they're pretty expensive right?

Wish I had one I could swap in, only other bike is an 04 450exc..I doubt they're the same cdi box?

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Try the cap first. I started pushing on the wires into the box and it started. I bought a used SX 450 one off KTM talk and it really made the power better overall. I’m actually glad it went bad. Way snappier down low and rips on top. There are no carb wires on the sx one.

After I got the new one I started checking the old one with an ohm meter and one of the prongs would lose conductivity when I pushed on it. Maybe you can borrow one fom someone and see if it fits.

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I have a working cdi off 2004 250sx that is in perfect condition if you end up needing one. Thought I had a weak spark but it ended up being a worn out top end. So I have a spare.

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I have a working cdi off 2004 250sx that is in perfect condition if you end up needing one. Thought I had a weak spark but it ended up being a worn out top end. So I have a spare.

Cool, thanks i'll let you know for sure if i need it.

Seems like the cdi is in a bad spot on these bikes...right were the forks can hit it when the tires turned all the way

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What is the procedure to check the cdi with a dmm? Ground the one dmm lead and check each output of the cdi with the other dmm lead while kicking?

What about checkin the stator? Put the dmm on the wires coming out of the stator cover while kicking?

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I'm a noob so bear with me....you have the spark plug cap, and a cable coming off of that. take off the cap and trim a little off the cable on the side the cap connects to?

When checking with a dmm....take the reading from the spark plug cap itself?

The CDI is where?

So the spark plug cable has 2 ends, one end screws into the coil, the other end pushes onto the plug itself. The end that plugs into the coil, if you trim that end a bit, it will give you some clean copper to connect with the coil for a good connection.

With the multimeter, you can check many spots. I usually check the coil input as that will tell you right away if its getting ignition.

The CDI (black box) should be on the left side of the bike on the frame right below the top triple clamp. I'm not verse enough to know if its there or under the tank like on some other models.

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What is the procedure to check the cdi with a dmm? Ground the one dmm lead and check each output of the cdi with the other dmm lead while kicking?

What about checkin the stator? Put the dmm on the wires coming out of the stator cover while kicking?

Yep, one wire on the ground and one wire on the input to the coil.

Checking the stator can be done the same way. Just pull the stator cover and find which 2 of the 4 wires goes to the coil vs the timing sensor.

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thanks for the help...yeah the cdi is up on the frame by the triple clamp

I'll check all these things later and report back, was thinking about taking it to the dealer but I think I should be able to diagnose it now

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ok so I need some help. What setting do i use the dmm on...ac/dc/ohms?

There's 4 wires coming out where the stator is. I can use a dmm on these and see if the stator is putting out voltage or working correctly? And which set would I check...the pic shows the wires

Picture010-2.jpg

Also here's a pic of the wire the plug cap goes onto...it looks ok? There's like some wires on one side

Picture011-2.jpg

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