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2005 Kx 250 rebuild.

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So my buddy's bike hasn't ran worth a crap since he bought it so, I went to clean the power valve, after week's of jetting and no success and I looked into the exhaust port and the piston skirts are broken intake and exhaust side.... 👍. I took it apart and the jug is in perfect condition and there isn't any junk in the crank there is a good couple of inches missing on the piston... All I can think is that the owner before him a high school student seized it up and ran out of money so he threw it back together and sold it. The jug appears to be brand new and the crank cases look like they've been apart, as well as a very clean crank and cases.... as much material that is missing it would have gouged the cylinder walls up and made the bearing's in the crank have some issue's.... There is no piston material anywhere, it's weird.

So my question is this when I took off the stator cover a bunch of creamy white stuff that looked like water came out.... I'm wondering if there could be a leak from a water passage in the crankcases allowing water to get in there or if the gasket was bad it could have caused that?? The gasket is all that I can think of to allow water in there because I don't think that there are water passages on the left side of the engine and crank cases.... There is a bunch of water corrosion on the flywheel and inside of the stator housing.

I will post a picture of the piston after I find my cord for my camera. (It's way bad!!!)

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Ok so i dug a little deeper into the crank and found a little sliver stuck in the connecting rod so the cases are getting split and cleaned. but here is the piston and I'll take some pics of the stator housing tonight.

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Crazy that bike even ran! I guess you have to give it up to Kawasaki!

Good for you for splitting your buddies cases with him.

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Crazy that bike even ran! I guess you have to give it up to Kawasaki!

I call it fools luck I'm not a Kawasaki guy 👍 But anyhow Here are some more hopefully they show up enough to get a good look. The cylinder has marks but not like it would have had if that piston came apart in it. There is a lot of material missing.

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My stator housing looks similar. Use a new gasket and maybe some silicone around the clutch cable end.

That piston was in there too long, no doubt. Too bad, because the crank would probobly have been good. So slacking on a top end now cost a complete rebuild.

When you get the cases split, look up my thread "Soda Blaster" in the vintage section. That will clean out the stator area and look brand new. Rinse the residue (obviously) real good before you assemble. Baking soda is an abrasive, like fine sand.

Keep the pics coming! 👍

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My stator housing looks similar. Use a new gasket and maybe some silicone around the clutch cable end.

That piston was in there too long, no doubt. Too bad, because the crank would probobly have been good. So slacking on a top end now cost a complete rebuild.

When you get the cases split, look up my thread "Soda Blaster" in the vintage section. That will clean out the stator area and look brand new. Rinse the residue (obviously) real good before you assemble. Baking soda is an abrasive, like fine sand.

Keep the pics coming! 👍

Silicone around the wiring harness boot too

@sledtrash You would be surprised what these cylinder's can go through my brothers bike chewed the piston skirt and ruined the head and bottom end but the jug came out fine.

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Silicone around the wiring harness boot too

@sledtrash You would be surprised what these cylinder's can go through my brothers bike chewed the piston skirt and ruined the head and bottom end but the jug came out fine.

I know that they can go through a lot but usually if a piston explodes it does so after the skirt catches an edge because the piston is wore out... We see this a lot on snow machines but almost always their is a gouge in the cylinder and pieces in the crank case.... as I said with all of the material that is missing it had to go someplace.... and it's not in the crank and not anyplace else.... so it had to have been cleaned...

I've got to buy a flywheel puller, and a crankcase separator. Then I can rip it apart and put a new crank in and hopefully not find any more problems...

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So I just got parts for my buddies bike.... his wife bought him the piston and rebuild it.

But I need a manual to help with exhaust valve assembly with the bike.

Torque specs and other things.....

Any help??

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Problem........ I got the top end all back together and then I tore the clutch cover off and the trans oil is gray..... what could cause that??? I'm thinking pieces of the piston skirt ruined the seal on the crank to the transmission..... But that wouldn't explain why the oil from the transmission wasn't in the crank. Hmmm bummer no Christmas surprise for my buddy... :bonk:

Edited by sledtrash

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lol so you didn't split the cases. That's one hell of a risk on your part.

Yep your buddy has one hell of a surprise coming and I think it goes by the name of "bottom end failure"

As for the oil in the gear box that's a bad water pump seal...

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Grey?

It turns grey after it's used for 2-3 rides from clutch wear. If you're worried about a seal problem then pressure test the engine. There's instructions in the stickys.

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With all of the bikes I've had I've never seen oil this color before come out of a tranny.... I thought about it over night and the only thing that makes oil turn white or grayish is water so maybe my water pump seal is bad....

"Edit"

Moose: We cleaned the crank out really good and had several mechanics look at it and they all said it looked fine (not that you can see much of it).... We didn't get any junk out of it so I'm not sure but I think it will be fine.... he's newly married so funds aren't the highest so hes alright with passing up the crank being replace.... We'll see I might be eating my own words in the near future... But.... if it is water in the trans I think I'd feel better splitting the cases and cleaning the entire thing with solevant before running it I'd hate to have the water wash some oil off of a bearing and cause some rusting and seize something up ..... so If I split it I'll replace the crank.... maybe buy it for him as a christmas or birthday present.....

We'll see....

Thanks for the input :bonk:

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So i finished splitting the engine apart and went through and replaced all of the seals and the crank breaings took every gear and shaft apart and cleaned the nasty oil water combinating out of every nook and crevice in the engine took the crank to a machinist and all tolerances were withing mark and all of the bearings in the trans were cleaned and then lubed and tolerances checked. Got it all together and the thing runs like a champ good low end grunt and a very hard hit on top. Harder hit than my cr250 but more managable if that makes any sense...

I am a little concerned however about the nasty vibration throught the foot pegs. It has been three years since i rode my cr250 but I dont remember that much of a vibration....

All in all it runs great and for less than $350 he's got a rebuilt rip roaring two smoker....

Now he just need sto learn how to ride.... haha his first bike two years ago a 81 kawi 125 he ran into a tree and ripped himself up pretty bad this one will take some getting used to!!

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There are some pic's of my home made main bearing puller, and the cases. When things started going together I really needed someone to take pics as I did it because once I got all of the parts it flew together. 👍

I rode it this weekend and got it pretty closely tuned in for him!!!

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Edited by sledtrash

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Sorry i rearranged my photobucket and it screwed up the pics.... i can re-add them if needed

Edited by sledtrash

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