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2004 EXC to SX Applicable Years

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hey guys,

Recently acquired a 2004 KTM 250 EXC. I'm looking for more power, better response. I've searched, but can't find an answer. What year heads and CDIs from 250SXs will fit my 2004 250 EXC?

thanks for the knowledge.

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tune the carb , put on a gnarly pipe for more bottom end and measure the head squish and then have your head machined

as for cdi pretty sure 2003 -2007 all the same ?

Edited by kxrob

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9 hours ago, KTMRider4Life said:

I'm not a fan of the gnarly, more bottom WAY LESS top and overall power as well.  Fatty will give you more power.

i guess this depends on where the OP needs his "more" power

if his looking at a exc i am assuming tight trails

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1 hour ago, kxrob said:

i guess this depends on where the OP needs his "more" power

if his looking at a exc i am assuming tight trails

I'd say overall the gnarly makes less power but I digress.  On my 300's I preferred the fatty over the gnarly even on the tight stuff.  Then again I think the 200 is even better.  

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with a 300 you can afford to give up some bottom end but not on the 200 IMO

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Thanks for the replies so far.

I have a gnarly and fatty pipe for it, fatty is currently installed. I like a lot of hit out of my two strokes, it makes me grin. But, I'd like to be able to switch back if i decide I need a smoother power delivery for trails, so I'm hesitant about trading. 

 

I know tightening the squish can net some good gains, but I also know that the combustion chamber on the sx is smaller and more hemispherical. Does it make much of a difference over tightening the squish band? How tight can I go before rod stretch turns my piston into a hammer?

 

And back to the original question- does anyone know year compatibility?

Edited by hickskateboarder
Autocorrect makes me look stupid.

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On 4/21/2017 at 9:51 AM, hickskateboarder said:

Thanks for the replies so far.

I have a gnarly and fatty pipe for it, fatty is currently installed. I like a lot of hit out of my two strokes, it makes me grin. But, I'd like to be able to switch back if i decide I need a smoother power delivery for trails, so I'm hesitant about trading. 

 

I know tightening the squish can net some good gains, but I also know that the combustion chamber on the sx is smaller and more hemispherical. Does it make much of a difference over tightening the squish band? How tight can I go before rod stretch turns my piston into a hammer?

 

And back to the original question- does anyone know year compatibility?

I don't know year compatibility, but suggest looking up part manual numbers may give you some answers. Before 2003 they used a gasket I believe, and an "O"ring thereafter. There were some bolt size changes too, but I cannot remember the years. I think 2003 to 2008 are the same, but check it out. Old memory getting near full.

As you get the squish tighter it is diminished returns so no real need to get very tight. 0.030" is as tight as I'd run it with 0.040" being fine too. If it is over 0.060" you are missing some potential power. 

The hemi chamber helps high rpm power. Tighter chambers (more compression) helps very low rpm power but at the expense of heat and piston life. Where do you want the power? The torroidal head is a great all around head unless you want peak power, then go Hemi and high rpm pipe. 

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