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I bought this bike 8 months ago and it ran like a champ since I got it. The guy I bought it off of had the bottom end completely rebuild right before I bought it off of him, he had receipts showing the bottom end was only done 2 weeks before I bought the bike. Well I went out riding yesterday and in the middle of hitting a hillclimb it locked up and shut off on me. I was reading that wiseco makes garbage crankshafts but I wasn't sure if it was just because it was a wiseco crank is why it failed or if I was doing something wrong. The synthetic looking stuff they put on the crankshaft melted and seized my connecting rod.

It's a 1999 KX250 

 

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Edited by Klutch616
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1 hour ago, mudmixer said:

Did u spray brake clean or something on the crank for inspection or was it that dry when you took it apart?could u post a pick of the piston underside.

It was dry when I took it apart, and yeah I'll post a picture of the underside of the piston. My oil and coolant were both topped off when it happened. 

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Well I doubt it was something u did I would say u got one of those cheap @$$ wiseco cranks,like playing Russian Roulette ,time to rebuild it with a factory kawi crank and factory bearings.i would still like to see some pictures of the piston.how much oil is sitting in the bottom of the crank case?any at all

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And the color of the stuffers and the fact that they melted.  But I want to see the indisputable, stone cold proof.

Buying a bike with a "fresh rebuild" used to be a good thing.  Seems to be the opposite these days.  People buy cheap stuff and dump it off on somebody else.  Would rather have a worn out original motor and do it myself. 

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I took some more pictures sorry I was busy with the holiday weekend. Luckily the guy gave me the original crankshaft that he took out of it. He said there was nothing wrong with it so I'm not sure why he even replaced it. It has a little bit of surface rust on it but I'll use some scotch brite and clean the surface rust off of it, oil it up, and get a case splitter and put that one back in. 

Also my air filter is clean I have 2 filters and I keep one sealed in a bag with filter oil and I'll swap them out each time before I ride. Along with changing the oil regularly. 

Last picture is the original crank he gave me. 

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And some idiot put a sleeve in it too.  Dang.  They did a fair job of it but it looks like the porting could use a few adjustments.  The boost port should be opening the same time as the main and sub transfer ports and it looks like they didn't bother to do that.

Would probably be helpful to smooth and blend the sleeve into the transfer port roof too.  This is a very important area.  Bummer is that you shouldn't even have to do this stuff if it was replated like it should have been.  If it runs good you could just put it back together but it would run better done correctly.

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