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Xr400 no spark

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Hello everyone I'm new to the forum but not new to dirtbikes, I recently picked up a 99 xr400 for a pretty good deal. Was in decent shape when I got it just needed some tlc. I was riding the other day and got in some mud so I sprayed the bike off.... One problem, now I have no spark whatsoever. I've changed the plug and coil. I've searched the forum to see if anyone else had this issue as well. I tried doing the cdi in the oven trick in case moisture was in the box, no luck. Please help as Im stuck where to go from here. I love this bike and I really wanna to riding this weekend!

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ok so you pressure washed it?? you obviously have water in some thing do you have an air compressor? try blowing out around the plugs and wires spray connectors with contact cleaner. do you have a headlight on the bike? may have to take it off to access the wiring. disconnect the kill switch.  its just a process of elimination it worked before you washed it so that's got to tell you some thing.  good luck with it and  let us know how you went

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I just sprayed it with a hose. I blew every connector off with an air compressor as well. It has a headlight but the wires aren't running to it (there's no bulb)

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cool it was not the headlight that needs checking but the cluster of wires behind it. did you disconnect the kill switch? I would have to say it is some thing small only because there was nothing modified just washed. there is not a lot to go wrong with the ignition on these things.

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I did, I disconnected the kill switch and cleaned all the connections on it just to be sure. I was thinking it was water in the spark plug cap but when i swapped it, it was still the same thing.

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ok did you wash it with a rag or sponge? may have bumped a wire some where. and how are the earth contacts? do you have a multi metre to check voltage?

are you in America or another country?  this wiring diagram is for an Australian xr400r may help to track the wires?

xr400 wire diagram aus.jpg

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I'm in north America, I haven't checked all the earth contacts. I do have a meter tried checking voltage at plug but I might not be doing it right. I just sprayed it didn't scrub with anything

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probably better to check for voltage at the coil input and work your way back towards the stator/cdi box its just a process of elimination ps did you leave the kill switch un pluged? and do you have a wiring diagram for your model bike? I know the aus model is different to the American

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What have you done to determine the system definitely isn't producing "spark"?

Is that just your way of saying that it won't start?

You being new to the XR and not up on all it's little quirks, I'm considering the problem might not be electrical at all.

Edited by Trailryder42

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I've tried grounding it to cylinder head, can't see any spark at all. I even tried putting my hand on it to feel for shock with no luck. I have downloaded the service manual. I have left the Killswitch disconnected as well.

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HHmmmm ok well check out the earth contacts and check that the voltage is getting through and there is definitely no moisture in any plug connectors. do you have a mate with a similar bike you can bot the cdi box off to see if it has carped it self?

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Look at/track down the Blue/yellow and green wires coming out of the stator wire loom. Those are from the ignition pulse generator. Make sure those look good. Pull connectors apart and clean them.

Check the frame ground under the seat.

If you have the service manual then you have the multimeter procedures.

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HHmmmm ok well check out the earth contacts and check that the voltage is getting through and there is definitely no moisture in any plug connectors. do you have a mate with a similar bike you can bot the cdi box off to see if it has carped it self?

Unfortunately no, there's isn't a whole lot of xr population near me. I will check the earth contacts tonight and update.
Look at/track down the Blue/yellow and green wires coming out of the stator wire loom. Those are from the ignition pulse generator. Make sure those look good. Pull connectors apart and clean them.
Check the frame ground under the seat.
If you have the service manual then you have the multimeter procedures.

Will do I appreciate the info!
  • Like 1

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I'll say it again just for the f*** of it... Make sure the kill switch is not engaged.  Is the bike dual sported with a street legal kit or stock wiring?

Edited by tvscum

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I'll say it again just for the f*** of it... Make sure the kill switch is not engaged.  Is the bike dual sported with a street legal kit or stock wiring?

Stock wiring I have the Killswitch completely disconnected

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Finally got it to fire... I forgot to mention I'm colorblind as hell. Got my girlfriend to match the wires up that evidently got pulled off and she's running again! Thank you guys for all the help. Even though I feel like a complete idiot now...

  • Like 3

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Nevermind my post, glad you got it to fire.

Edited by nomad221

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Good show...... what was actually stoping the spark  in the end???? great to here you got the beast to live again!

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It was had zero spark whatsoever..it would sputter a little bit choke as soon as I took choke completely off she fired right up.

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ok that's a new one......iv never heard of the choke stopping the spark???

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