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Discussion Starter #1
I've been searching for a performance cdi for the 250x for a while now.Curtis sparks is the only one I know of.And it only changes your rev limit 1000rpm higher.I was looking for one like amr's cdi for the 300ex.It changes timing curves and boosts power in all rpm's.My question is if no body makes one of these for the 250x could you buy a complete 300ex harness and buy a performance cdi for the 300ex and put all of this on your 250x?The motors are practically the same so I can't understand why it wouldn't work.
 

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I don't even see where you would need a 300ex harness billy the only thing added to the harness is the starter circuit.

I have the wiring diagram for the 250X if you want it and just find the schematic for the 300EX and I think you will see that the colors are all the same. the CDI should be the same.
 

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Yeah, I agree with Moose. It will probably work anyway.
 

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Discussion Starter #4
Yes but the stator charges the wiring harness differently.Someone told me once that they put a 300ex cdi on a 250x and it wouldn't even start.
 

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Yes but the stator charges the wiring harness differently.Someone told me once that they put a 300ex cdi on a 250x and it wouldn't even start.
I would check it out, myself, instead of listening to what someone else says, unless you know them good and know that they know what they are talking about. Moose says he has a 250X wiring diagram and I might be able to locate a 300 EX manual if you need it.
 

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All you would need to know would be the resistance tolerations on both CDI and Stator components but I'm pretty sure they are the same.
 

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Discussion Starter #7
Well heres what I'm thinking.I've been looking on ebay and you can buy a used 300ex cdi for like $30 including shipping.I may just buy one and try it.If the stock unit works surely a performance one would.Or I could borrow one off of my bosses 300ex.
 

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Well heres what I'm thinking.I've been looking on ebay and you can buy a used 300ex cdi for like $30 including shipping.I may just buy one and try it.If the stock unit works surely a performance one would.Or I could borrow one off of my bosses 300ex.
That would work. Good ideal.
 

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Discussion Starter #9
I'm just not sure about doing this.I just don't wanna fry something.Why hasn't someone else ever asked this question.
 

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Discussion Starter #12
I hope so.But in my first question I asked about putting a 300ex wiring harness in it.Would this work without the battery and that.There is one on ebay with the coil and everything for like $50.
 

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Maybe the plugs are just different. If so, then, maybe the harness and all would work. If you just had part of an old 300 EX harness with the plug that plugs into the CDI, you could use the plug and just wire it to your harness, solder it, and put heat shrink tubing on it. The plug could just be different, that might be why they said it wouldn't work.
 

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I guess because the RPM ranges are pretty much the same so no one thought of installing a 300EX CDI on would be my guess??
 

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Discussion Starter #15
No the plugs are the same.And why didn't anybody make a performance cdi for the 250x?A lot of people race them right along side the 300ex's.
 

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If the plugs are the same, then I'm out of ideals. I can't see why it wouldn't work, though. I can't really see how the wiring harness would be that much different, but it could be different, I guess.
 

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Helmut I'm with you I don't think it matters about the harness but the regulator, and stator may have different ohm resistance ranges to make up for the starter system on the 300EX? buy one and try it the worst thing that could happen is you fry the CDI I mean it's nothing more than a capacitor . and they store energy to produce a more constant spark at a higher voltage.
 

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Discussion Starter #18
Well I just thought of something moose.My boss has a 300ex.It was his sons alos and no keys.So both the 250x and the 300ex have to be hot wired.And I know for fact to make a 300ex run with no key you have to unplug the wires from the key switch and reconect them staight together.But with the 250x you have to just unplug them from the key.If they are plugged together it won't spark.So the 300ex and the 250x's wiring are completely backwars because of the 300ex having the battery to charge.So my guess is that the capacitor/cdi only flows current one way.Meaning it wouldn't work.
 

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I bet the ground circuit is set up different. The CDI box on the 250X isn't grounded to the frame by bolting directly to the frame, is it?
 

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The key switch on the 300 EX must break the circuit and the 250X key switch must just ground the circuit to complete it the circuit.
 
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