2004 KX250 sparking at wrong time

Hi all,

I have a 2004 Kawasaki kx250 that died suddenly on me the other day. all i can get it to do is backfire every once in awhile. Tested the resistance and everything of the magneto and stator with a multi-meter and all is good.  Coil is new oem Kawasaki the reeds are brand new vforce and the top end and carb have been completely rebuilt.  key on crank is intact and all the timing marks are lined up. I hooked a timing light to it and spun the motor over really fast and found that it is sparking way to late.  The service manual says that it is supposed to fire 14 degrees before TDC but it is sparking way after TDC.  Im thinking its a fried CDI box since its the only thing i wasnt able to check.  Any help would be appreciated

 

Thanks  

The timing spec in the manual is at like 7000 RPM.  I don't know what kind of advance or retard it does at kicking RPM but it probably won't be trying to spark before TDC.  They don't want that motor running backwards.

It could be a bad CDI box but I wouldn't condemn it just based on that. 

Flywheel key ok - not sheared off ?

Flywheel key ok - not sheared off ?

Flywheel key is intact
The timing spec in the manual is at like 7000 RPM.  I don't know what kind of advance or retard it does at kicking RPM but it probably won't be trying to spark before TDC.  They don't want that motor running backwards.
It could be a bad CDI box but I wouldn't condemn it just based on that. 

This one is sparking after the piston has already started its downstroke
Just now, luke8500 said:


This one is sparking after the piston has already started its downstroke

And it probably should so it doesn't break your foot.

I would not expect a failing cdi to be late.  Typically it is working or it is not.

Is "really fast" spinning at 1,200 rpm?

2 hours ago, luke8500 said:


This one is sparking after the piston has already started its downstroke

Yes, that is after TDC.  I would expect it to spark anywhere from 5-10 degrees after TDC at kicking RPM.  This ensures the engine cannot start backwards and destroy the kick start mechanism.  With digital CDI they can do stuff like that.  The ignition advance or retard varies with RPM.

I also would expect a bad CDI box to be just plain dead.  Anything can happen but having one that is defective but still produces a spark is very unlikely.

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