05 yz250 ignition problems

I have an 05 yz250 that wont produce spark unless you press the engine kill button. it will spark once when u hit the kill button and then no spark. I went through the manual and measured resistance of the coil and spark wire lead, pick up coil on, charging coil 1, charging coil 2, and did a conductive test on the kill button, even diconnected it. Everything is in in accordance with manual with all the resistance numbers. I measured resistance on plug cap . Tried several spark plugs, replaced CDI, stator, coil, and cap. Checked ground block and it has all five grounds solid intact. Checked every connection point with meter. I have no idea what else it could possibly be. If anyone could help i'd really appreciate it. The only thing I have i mind is still the CDI, but the manual doesnt tell how to measure anything to check it, and thats a costly part to keep trying out. Thanks

my cr250r had the same problem but after changing the cdi and the coil i found out that my roost boost came un pluged and it would not give me a spark i dont know about ur yz if it has something like that but it ties in with the cdi box and is usaly conected to the frame by the steering colom i dont know if this helps but this was my problem with my bike

Hi there

The manual says that you have to check the stator, the coil, the plug, the wires and if there is still some fault in there the CDI has to be it. I worked through mine that way and bought a new CDI. It was the faulty part.

If you have a buddy owning a YZ250 I think 1999 to 2006 should work.

good luck


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