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Touching up the ports

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I am wondering if any of you have ever touched up the intake and exhaust ports yourself? I am not talking about removing lots of metal, just smoothing some bumps and casting marks.

BTW, I have an '05 CRF250R. Any additional "basic" info I should know about the head? I have to do a valve and piston job and just want to do as much as I can while it's down.

Thanks.

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I did my own ports with a dremmel tool.Both intake and exhaust.I polished them very smooth and seemed to work fine.Im not sure if i felt any power difference.I think the intake is supposed to have some grain not completely smooth it was posted somewhere.that was after i had already done it.

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I did my own ports with a dremmel tool.Both intake and exhaust.I polished them very smooth and seemed to work fine.Im not sure if i felt any power difference.I think the intake is supposed to have some grain not completely smooth it was posted somewhere.that was after i had already done it.

You read right, intake ports should not be completely smooth as this actually reduces flow. I'm about 10 years out of college, but it has something to do with laminar flow. Think the bumps on a golf ball I guess.

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You read right, intake ports should not be completely smooth as this actually reduces flow. I'm about 10 years out of college, but it has something to do with laminar flow. Think the bumps on a golf ball I guess.

Actually, the rough surface of the intake ports are there to create turbulence which helps mix the fuel and air together (which is why everyone says NOT to smooth out the intake ports). Laminar flow is different; it would be created by dimpling the surface (like on golf balls) of the intake ports which creates tiny turbulets of air that act like ball bearings for the air that passes over it ~ thus creating less drag and faster flow. However, that would have a negative effect and not help the air / fuel mix together properly.

I only know this because I did a lot of research on dimpling and Laminar flow a while back while porting my minibike's ports :banghead:

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