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Discussion Starter #1
bought a 2002 katana 750 and it had 10 000km original km so I got it home and the put a new battery in it and tried to start it and the cdi box started smoking really bad and had no spark. I ordered a new used cdi box off eBay and it only fired on two cylinders 2&3 so I thought it was cdi again so I ordered one of eBay used that was tested good and when it got to me it still fired on 2&3 so I swapped the coils wires and I get a spark in 1&4. I checked all the coils all 4 points get 11.6v so I ordered a signal generator coil pickup waiting for that but I don’t think that’s the problem. I know my issue is the white wire isn’t sending the signal the coil from the cdi so I get zero spark but I don’t know what to do now or where to look. The wires and plug to cdi all look fine I even ran a ground jumper from bat to frame this has been like a year I haven’t been able to ride it any advise would really appreciate


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IF that is the "typical" design for a metric 4 cylinder, the spark goes to 2 cylinders in series.
So if there is an open anywhere in either plug wire or plug then both cylinders of the pair will fail.

BUT.....since you were able to get spark to both pairs at one time or another, that likely is not the problem.

Puzzling situation.
 

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I would suspect it is the signal generator. The wires you swapped over are the ones getting a signal to fire. Even though you are getting voltage to all coils the signal to fire...the signal for the primary windings voltage to drop thus inducing a voltage in the secondary windings is not getting to the ones for 1&4. The only reason should be the signal generator is not sending that signal...IMO

good luck
 

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Grab a service manual...can be found from Google at either manualslib.com or other site pdf free...follow step by step directions and test resistance on electrical components that are essential for spark...if the unlikely scenario where everything checks to spec...test continuity in harness...i could show you how easy it is..(time consuming) but easy with direction and patience..you've got a bad coil,wire,ground,connection and or electrical path...3 things to run a motor..fuel,air,and spark right? Electrical just so happens to be the very unhappy spiteful ex wife of the three..im in school to be an aviation maintenance tech now and im learning the math to figure out what size your cylinder needs to be for your stroke and bore.... I always and probably forever will just order what I need from a company but I've been turning wrenches since I was 15 and I'm 30 now and I have worked I'm too many things to list I don't know everything about everything but I can chime in on a conversation for something that I've never put my hands on and I'm pretty pretty sure that I could at least be in the right ballpark

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Adding to prev message...you can pretty much test most of your electrical components without having to do anything other than and plugging them

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Not that it has any bearing on this specific problem but .........................
In another thread recently, a rider was having spark trouble and it turns out that he had gooped dielectric grease on his plug threads instead of anti-seize. Dielectric grease is an INSULATOR. His plugs weren't making good connection with the block. With an I-4 design, an open like that in just one place can kill TWO cylinders.
 

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Discussion Starter #8
I’ve went through everything it’s gotta be the cdi box again it was a fluke getting two bad ones of eBay but I ordered the dyna 2000 digital ignition system both coils measured 2.9 ohm. I know this has two fix it but would you take the old cdi box wires and remove them from the harness?


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If you suspect the harness wires then I would be doing that first before buying any other parts. A simpler way would be to disconnect the original wires and wire the CDI box direct outside the harness. If it works then you have found the problem.
 

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Discussion Starter #10
I went through everything the harness is fine I the ground was bad idk if it could of caused the cdi box to short


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I went through everything the harness is fine I the ground was bad idk if it could of caused the cdi box to short
Please do something to separate your sentences.
A post all run together like that is hard to read and understand.

A bad ground can cause the CDI to mal-function but not likely to burn it out.
 

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Discussion Starter #12
I bought a dynatek 2000 digital ignition and it fixed it all I can assume is it was a bad cdi box.


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