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2001 KX125 Piston size

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Hi guys!!! I'm having a problem understanding this. I need to rebuild my top end badly, and the piston size I believe is a size-C piston which is a 53.97mm piston. This kit on ebay is a great deal for everything you need to rebuild a top end but it says its a size-A piston which is 53.94mm. Is it possible for me to use this kit in my bike? here is the link please look at it because it would really hep me financially if it can work.

http://www.ebay.com/itm/Namura-Piston-Gasket-Kit-2001-2002-Kawasaki-KX125-KX-125-Standard-Bore-54-00mm-/290777110202#checkout

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I read it, but I really don't understand still. Yes the piston is .00005 in. lager, than an A size piston, but would it work with my cylinder?

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Since you are going to a larger piston you "should" measure the bore. To be safe, put the same size piston back in or buy a forged piston. You may use the A piston if you have a slightly worn cylinder, which a measurement will determine.

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Jeekinz thanks for the help, I measured the bore with my bore gauge and its a 53.95mm. but the problem is, is that now there was some water in the cylinder, and watery slug on the cylinder head, so now I have to clean the cylinder of little rust and clean the head. Any idea of what would've caused it?

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What do you mean "water"? Like a blown head gasket or something? Just make sure all the gasket surfaces are clean and flat before you put it back together. Clean the powervalve with oven cleaner.

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That's the problem the head gasket wasn't blown everything was fine, I even checked the pump gaskets and they were fine too. I'll add pictures of the head, cylinder and piston

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If there's coolant in the cylinder it can only come from a bad head/base gasket or cracked cylinder or cylinder head. If there's coolant in the trans or right side cover it's from the waterpump seal/shaft. It's not like a car engine where there's 100 places coolant can come from.

Edited by Jeekinz

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The cylinder head had what looked like white froth on it and it felt like a watery sludge with fuel mixed with it. The cylinder has little rust in it but you can be it in the picture. The piston looks like it ran with water burning on it that's why it's kinda brown I guess on top

IMAG0193.jpg

IMAG0192.jpg

IMAG0191.jpg

Edited by mototimothy8

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You can't see it in the picture, but the owner said it was ported and jetted properly. When I first took of the head and looked inside the cylinder, there was the little nics on the inside of the exhaust port and on the intake ports. I come to find out next is that there a lots of nics below the jug next to the crankshaft but not on them. Also the top of the jug can these nics in 2 spots around the rim of the cylinder, but not as significant as the ones in the ports. I will upload pics when I get home because I'm in class now but will do it when I get home.

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On your 125, water passes through your cases so it could be a leak between the cases. You need to assemble everything and pressure test the cooling system. It's hard to diagnose with it all apart. If the trans oil was fine than the waterpump seals.shaft are good.

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There was no water in the trans oil. could it be from the rough job the previous owner did to do what he called "porting"? So the crank and everything is fine there, but I still don't know how this could've happened. If it helps with anything, my compression was lucky to get to 100 psi, which started this whole piston thing and now I ran into this problem.

Edited by mototimothy8

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Those nicks sounds like a piston let go at some point in it's life.

There was no water in the trans oil. could it be from the rough job the previous owner did to do what he called "porting"?

No. Unless he slipped with the grinder and ruined a gasket surface.

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Okay.. Its really bugging me that I can't show his porting job. The area at the bottom of the jug that sticks out a little further to go into the bottom end has be noticeably ground, filed, dremeled down. Correct me if I'm wrong but I believe that's how some coolant goes through the jug.

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