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Top end rebuild newbie

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I have a 2011 kx450. It has about 75 hours on it and I want to do a top end rebuild. I have looked on YouTube for instructions and have found some help. What I am looking to find out is, what exactly do I need to replace? I know I have to replace gaskets, but does the head normally have to be replaced? How much am I looking at spending to do a "top end rebuild"? I know I can get it apart and back together and do the work. But I don't know exactly what needs to be done. Any suggestions would help. Thank you

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The bike starts first or second kick and seems to run fine. It has a little bit of oil coming out of one of the vent hoses coming from the engine. Not dripping but there is residue there after riding. I was told that means it's time for a top end job.

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If you don't have the service manual, I'd suggest getting that first.

The signs for piston wear are generally burning oil and ring blow by.

When ring blow by occurs, you'll have more oil coming out of the crankcase breather than normal.

You can pull the valve cover off and check valve clearances without having to replace any gaskets. If those are out of spec, you'll need either specific shims, or a shim kit.

If you conclude that a top end rebuild is necessary, then follow the service manual instructions, which will give you a list of parts that need to be replaced.

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The bike starts first or second kick and seems to run fine. It has a little bit of oil coming out of one of the vent hoses coming from the engine. Not dripping but there is residue there after riding. I was told that means it's time for a top end job.

That's common on these bikes to have oil residue there, but at 75 hrs it would not hurt. I did my friends at 70 hours and it was all in spec. We just put in new rings and a timing chain and all was good.

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