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KX250 crank questions

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I've got an '01 motor i'm in the process of rebuilding (I had another post about it, it had a problem with the crank sliding in the main bearings).

I've got a spare crank that came with some parts that I don't know the history of. It dosen't have any vertical play in it and it's within specs for side-to-side.

Any other tests to determine what kind of shape it's in? It seems like big end failures are relativly common on these bikes. Is there a cause, or just general wear? Is there a specified or recommended replacement interval? I didn't see anything in the (clymer) manual.

Thanks

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It seems like big end failures are relativly common on these bikes.

Nothing different than any other 2 stroke.

Personally, I wouldn't gamble on a crank I didn't personally know the history of. A new Wiseco crank is $180, cheap insurance.

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If you do choose to use it, very carefully with a good light look at the lower rod bearing's cage and rollers while holding the rod and using a pick tool rotate the cage and LOOK at each roller and the cage for ware. There is no for sure way to know how long it will last and it is up to you, that said a friend of mine's kid blew his 98 KX250 last year and I put a used one I had laying around in it and it has held up fine but it is a gamble for sure.

Ed

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I totally agree with Ed..looking at the cage and making sure the needles all look shiny and smooth action. You should be able to slowly rotate the rod and feel the needles for smoothness.

I would just about bet on a well checked used OEM crank from Kawasaki Japan as a new Chinese built Wiseco for reliability....and thats nothing against Wiseco....just China in general...lol

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Why would you go to all the trouble of splitting the cases to install a used crank, and take the risk that you may be doing it all over again soon? Get a new crank.

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bought my entire wiseco kit off fleabay for $187 including shipping. it included crank with rod, main bearings and seals and all other seals and gaskets to do entire bottom end. cheap insurance and peace of mind for sure

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bought my entire wiseco kit off fleabay for $187 including shipping. it included crank with rod, main bearings and seals and all other seals and gaskets to do entire bottom end. cheap insurance and peace of mind for sure

same here,just under $200,did the rebuild myself and have a full season so far with no problems.Wouldn't hesitate buying another for this price.Even if you had to do it every 2 or 3 years its still not that bad.

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So no absolute way to determine if the used crank is good other thank running it and seeing if it blows up?

Yeah, then i'll probably buy a new one.

Thanks for the input everyone

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So no absolute way to determine if the used crank is good other thank running it and seeing if it blows up?

Yeah, then i'll probably buy a new one.

Thanks for the input everyone

Checking the specs will tell you if it's still within wear limits. It won't tell you how much life is still left.

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Nothing different than any other 2 stroke.

Personally, I wouldn't gamble on a crank I didn't personally know the history of.

A new Wiseco crank is $180, cheap insurance.

And cheaply built, low quality insurance...

Edited by youngztr

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And cheaply built, low quality insurance...

I never tried a weisco, I bought a HotRods crank a couple of years ago and havent had any problems with it. It was about the same price as a weisco, but I had read complaints about them here, so I went with the Hotrods, glad after hearing even more complaints now.

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