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Used athena bigbore questions

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Hi

Having a athena big bore kit (290cc) from a older yz250f with about 15-20 hours on it and was planning on putting it on my -08 250f byt when i faced (with a 1200gritt paper on a piece of glass) i saw some pores or pitting in the cylinder bore and on the seal surface.

Is this normal? can i just assemble it and go ride?

The rest of the bore looks fine.

I cant feel the marks with my nail but with a really narrow edge you can feel something.

30594764.jpg

30594763.jpg

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Is it normal to having pitting in the cylinder wall? No, I wouldn't install it like that. It's hard to tell how deep the pitting is, but it doesn't look like it can be honed out. I'm not sure how much of the wall can be bored on the Athena, but on a normal cylinder I would bore it over .20 and have a fresh cylinder. You would then have to match a piston and rings to it.

Do you know what did that? Did some metal get in there?

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That is a nikasil bore and boring oversize is not a good option on that. I have installed two used athena cylinders and have not seen porosity like that on either one. I think you have 3 choices:

1. Call athena and see if they might have had some cylinders get a porous coating and if so maybe they will help you out on re-coating or replacing it.

2. Run it and see what it does, your just out your labor and a head gasket it it doesn't run good

3 Shell out the $$ to get it re-coated yourself.

I personally would do all three in that order. Let us know how it turns out.

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Yes i think i`ll just mount it and try , im just gona talk to a guy who is more in to this and does alot of motorwork. if he says no no i`ll try to get the guy i bought it from to take it back and refound me.

A new athena kit cost about from $1100 (yz250f -08->) and $1330 (wr250f 08->) whats the difference ??

A pistonkit $400

A gasket kit $ 175

Crazy prices- thats way a bought a used one, if i get refound i`ll buy one from ebay , a je-kit or similar,(can i use a athena piston in that cylinder?? i have already bought a new 82,96mm athena B-size piston))

I`ll just thought it would be fun to hear your thoghts about it.

I bought this stuff used and unseen

btw i mailed Athena this evening, i`m gona be suprised if they answer at all.

thanks alot //Henric

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From the picture it really looks like spray paint over spray. I see it on the gasket surface as well. Either that, or the guy welded with the cylinder right beside what he was welding.

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From the picture it really looks like spray paint over spray. I see it on the gasket surface as well. Either that, or the guy welded with the cylinder right beside what he was welding.

Good catch! Since it looks like it is on the gasket surface it can't be a coating problem.

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Talked to a engine builder a the said that there was no big deal, thoug i need a new piston since there was an 2001-2007 piston type with the cylinder when i bought it.

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