Changing a piston

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Road Dawg
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Changing a piston

Post by Road Dawg »

Okay, I have a 98 & 03 KDX 220r. I want to change the piston but I have never done this. I do have a service manual, but it does not look in the 98 like it explains it well enough for a first timer. I don't wanna screw the bike up.

I really don't want to take it to a shop. I am pretty sure I can do it if I have all the info. I know you have to support something at some point when doing this.. I just am not sure of what or where it's located. I watched a video on RockyMountainATV's website. It's a yamaha that they're tearing apart. I assume a KDX is probably similar. Anybody wanna tape a piston change on their KDX for me.. haha !

Any help would be appreciated.

Thanks
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KDXsg
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Post by KDXsg »

experience does make a difference in doing the top end. most first timer face problems in taking out the old piston pin (after prying out the circlip on one end) because of prolong used and some carbon built on that area. special tool needed or you can use similar size hex socket to tap tap the pin out taking care not to damaged the con rod.

putting back the pin is easy but putting back the circilp while the piston is on the con rod is challenging. use used old paper or cloth to block up the crank area to prevent the circilp to drop in to the crank case before prying out and before prying in the new ones. (you will like to first pry in the new one into one side first before installing the new piston on to the con rod and then pry the other end circilp)

coating some 2 stroke oil while installing most of the parts help to ease the installation.

take note to wear the piston should face by following the arrow on the piston face. and which piston ring to go on top and below.

never reused old used gasket. the psiton should have a pin on the ring groove on both. while installing the cylinder, align the top rind end to the pin and squeeze the top ring and then silde the cylinder over and do that also to the bottom ring. that is the only way that the cylinder is going to go back in. apply some 2T oil to the rings to aid installation.

the rest should be easy to folloe the muanal.
A true KDX customizer!!
Jupiter2
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Post by Jupiter2 »

I'm with ya on this one Road Dawg. I haven't done a top end yet but I plan on it soon and i'm trying to come up to speed. I think the shaft that needs to be supported is the Exhaust Valve Actuator Shaft. Correct me if i'm wrong guys because I need to know this too. You need to support the shaft when removing the nut. (compliments of the online manual)

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2000 KDX 200
2002 XR200
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KDXsg
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Post by KDXsg »

yes you are rite.
A true KDX customizer!!
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