Is cylinder porting worth it for tight trail riding

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Curious George

Is cylinder porting worth it for tight trail riding

Post by Curious George »

I'm sending the heads out to RB Designs for machining , but is porting worth the money spent ? We're not racing , but more torque would be nice.
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Jeb
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Post by Jeb »

Do you have the 200 or the 220?
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Post by Curious George »

A 2005 220 and a 2006 200
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Indawoods
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Post by Indawoods »

The head and carb mods should be enough for you.... Porting is not recommended on the KDX... it is pretty much optimal for reliability.
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Post by Curious George »

How does it help reliability ? By taking the sharp edges off the inside ports ?
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Indawoods
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Post by Indawoods »

Obviously your idea of porting and my idea of porting are two different things. Nevermind...
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Post by Curious George »

>|<>QBB<
Indawoods wrote:Obviously your idea of porting and my idea of porting are two different things. Nevermind...

Explain ,,, I understand porting / blueprinting .

Were you saying that you'd sacrifice reliability if you got too aggressive with porting ?
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fuzzy
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Post by fuzzy »

Yes, you can. Little cleanup stuff is OK. Little more is OK too depending on what you're after. Porting is generally to alter the power curve of the motor...Like a cam on a 4T(except you can't change cams...just cylinders...LOL). What don't you like about your power curve? You'd be amazed at that 1mm does, and you can ruin an engine by porting it. I've seen plenty that people paid for what I would consider trash when done. (wow, I have 4 more HP at 8k, but all my idle to midrange is gone, and my carb is impossible to tune). More than a little can result in having to do other things...Different ignition map, timing change, need to run race fuel, completely different slide/needle/etc in carb, etc. Higher strung, race fueled beast will lost some reliability/longevity.

In general I think 125/250's with a drum-style powervalve have a lot more wiggle room when it comes to porting, and it's much more common there. They generally come setup 'in the middle' can some grinding can be done to get more low, or more top. The KDX's porting is much more unique, and that's why a lot more so called experts trash the cylinders when doing 'typical' things.

Just posted more about this in the "EG Porting" thread too.
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