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YZ 250 Cylinder Head how to

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I have a 2004 YZ 250. The head gasket had a leak in it last year while i was riding it and the piston melted and now i cant get it to come off the cylinder head. I thought about using sand paper but i know that can really mess something up. Any ideas on how to get it off?

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Some pics would be nice, they always help.

My advice would be to send the head to rb designs and let him work it over for you.

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If then piston is stuck to the head, then things are already pretty messed up, big time.

I second a pic

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I assume you mean the piston is stuck in the cylinder bore.

The only thing you can really do is take the head off of the cylinder and try to lightly tap it out with a wood or plastic dowl and a rubber or plastic hammer. raise the cylinder up off of the cases about 1/2" and place two wood or plastic blocks (5" or 6" long) in the gap between cases and cylinder. this will allow you to tap on the piston without bottoming out the crank/rod.

It's likely that you either broke a ring, or caught a part of the piston skirt in the porting. Try to look through the intake port and exhaust port to check for snags. Look carefully, use a dental mirror in the transfer ports with a small flashlight.

If you beat on things too hard, you can pretty much kiss that cylinder goodbye if it isn't alread wasted.

If you get the piston out, check for chips and dents in the plating and also check for aluminum that has bonded to the cylinder walls near the exhuast port. That stuff must be repaired / removed.

Pics would really help if possible.

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Some pics would be nice, they always help.

My advice would be to send the head to rb designs and let him work it over for you.

Yup. Once you get the parts apart, Ron (rb-designs.com) is the way to go. If you need it plated, lot of folks have done well with PowerSeal.

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Ron (rb-designs.com) is the way to go. If you need it plated, lot of folks have done well with PowerSeal.

Agree on both recommendations.

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