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Cylinder/Piston Condition.

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I bought a used 06YZ250F from a dealership back in November of 08 and rode it twice only to figure out that the valves were at the end of their life cycle. I tore it apart and sent the head off to have the seats cut and new valves put in. Pretty much everybody told me I should probably replace the rings, piston, and cam chain as well. Keep in mind that I really didn't know much about the history of the bike other than the previous owner raced it and "maintained it well." I've probably only put about 3-5 (My guess.) hours on the bike total since I've had it.

How does everything look? I think the cylinder looks great (crosshatching). I don't really have an opinion on the piston.

http://s628.photobucket.com/albums/uu8/usernts/?albumview=slideshow

Also, how much play should there be between the piston and cylinder when there are no rings installed? I can see a gap and feel it rock back and forth a little in all directions. I'm not sure but the play seems excessive.

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I bought a used 06YZ250F from a dealership back in November of 08 and rode it twice only to figure out that the valves were at the end of their life cycle. I tore it apart and sent the head off to have the seats cut and new valves put in. Pretty much everybody told me I should probably replace the rings, piston, and cam chain as well. Keep in mind that I really didn't know much about the history of the bike other than the previous owner raced it and "maintained it well." I've probably only put about 3-5 (My guess.) hours on the bike total since I've had it.

How does everything look? I think the cylinder looks great (crosshatching). I don't really have an opinion on the piston.

http://s628.photobucket.com/albums/uu8/usernts/?albumview=slideshow

Also, how much play should there be between the piston and cylinder when there are no rings installed? I can see a gap and feel it rock back and forth a little in all directions. I'm not sure but the play seems excessive.

Look in your manual for the tolerance from the cylinder to the piston. That cylinder looks like its in good shape to me. How is the crank and main bearings? Do you have any play in them? For the top end I would just put a new 08 oem piston in it. I think that cylinder is just fine. Pistons can look good with high hours on them but it doesnt mean they arent ready to come apart. I replace the piston every 30hrs in my sons bike but he races all the time and is an intermediate/B rider. You may not need to do it that often depending on how and what you ride. :)

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I don't really have the equipment to measure tolerances and I've already ordered the 06 OEM piston. :S I wish I had thought about the 08 piston before. I guess I was just too excited to order the new parts and it slipped my mind.

I got the piston, rings, wrist pin, circlips, gaskets, and a cam chain for $92. :)

I'll check the crank/rod as soon as I get the chance.

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Hey,if you can send that piston set up back,get the 08 stock stuff.I did this on my 06 over the winter along with the 09 needle mod(cheap).you will notice more low end pull,well worth it.

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Love the Graphics kit!!!

I would definitely reccomend getting the 08 piston. Llike the revious poster mentioned it is well worth it.

BTW... that cylinder looks brand new. Certainly seems like a well maintained bike.

Good luck!!

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Love the Graphics kit!!!

I would definitely reccomend getting the 08 piston. Llike the revious poster mentioned it is well worth it.

BTW... that cylinder looks brand new. Certainly seems like a well maintained bike.

Good luck!!

I don't think I'll be able to send back the 06 piston, but I could try. I don't really know anything about the dealerships return policy. lol

I will look into the 09 carb needle though. Thanks for the suggestion.

I photoshopped the gfx for somebody in the pictures/video section.:)

http://www.thumpertalk.com/forum/showthread.php?t=757939

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