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So my wheeler died on the trail...we opened it up and took a look...come to find out the piston skirt was shattered....however the top and ring were untouched....the cylinder walls look great!

My guess, the guy I got the wheeler off of realized an issue began...I am guessing he decided to get rid of it before something big happened...well it happened...it had light compression but still ran strong or somewhat strong...It looks as though the skirt began to break away and slowely sontinued to break and discharge through the exhaust over time...finally a big enough piece came off to jam the piston and drop the compression th about 57psi....

Any idea what could cause this? What do I need to do to prevent it from happening again? Here are some pics if this helps any of you to diagnose for me thanks.





 

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One more issue I almost forgot....when I tried to drain the radiator it seemed there was nothing in it or atleast nothing came out the drain but the engine was full of coolant and the filler container was where it should be....
 

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WOW thats a mess!
 

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i don't see how you got so lucky by not scarring up the walls when it came apart. i hope you found all the fragments. let us know whether it needs bored or not and what is out of. surely they didn't just throw a set of rings in it and put it up for sale.
 

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where are my piston skirt fragments most likely to be

My scrambler 400 not only shattered the piston skirt but also put a 180 degree crack at the front base of the cylinder (the crack went right around the front two cylinder mounting bolts). I bought it like this, I was told it had a cracked head (yeah right). Anyhow, my question is where am I most likely to find the broken piston fragments ? I can hear a noise that sounds like a piece rattling around somewhere when I move the connecting rod and crank by hand but I can't tell where the noise is at exactly (would most of the fragments have found their way out the exhaust ?) What should be my concerns about this if I can't find any fragments ?. I would appreciate any input on this issue before I go ahead and order up a new cylinder and piston kit. I had a broken skirt on a kawasaki bayou one time and I found the piece just below the oil pump screen but that was a four stroke.
Please help - Thanks...
 

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split the cases and clean it out is the only way to do it right, or do it the half ass way and put a piston in it and ride.
 

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cracked skirt, split cases to remove residual fragments

YUK !!! as much as I didn't want to hear about needing to perform such a task, I still very much appreciate your suggestion. Is there an area that any chunks could have ended up other than out the exhaust ? I am unsure to the fact if the previous owner may have already removed any chunks or if they have already been ground to dust or if they could have gotten anywhere other than below where the connecting rod connects to the crank. I imagine quite a bit could have already made it out the exhaust ? I am not too concerned about any aluminum dust but when it comes to chunks I become worried for good reason.
- Again, THANKS for your help on this matter. - Scotmo...
 

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the right way is to take it apart and clean it. skirts do fail sometimes on their own, and make sure you clean out your exh, I've seen pieces of exh get back into the engine on 2 strokes.
 

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broken skirt fragments

Thanks for the tip, it is very much appreciated. I am still going about this task gingerly trying to gather opinions and searching for deals on replacement parts. I notice a noise when I turn the crank by hand the best way to describe it is as if a bearing has lost a ball or maybe like the oil on the crank is acting as a glue substance picking up a fragment and the dropping it before it can make its way around. I think that I am going to use a piece of bailing wire to probe around and hopefully conclude what that noise is that resembles a piece of something falling and landing (perhaps under the crank where I can't see it) about half way thru the stroke in either direction that it is turned. If it is a bad bearing then of course in I go to do it the right way. I wish that I didn't have to do so much homework on this issue. Unfortunately I don't have enough funds for parts to do it the right way at the moment but it will probably come to that. It would be nice peace of mind to know that it was cleaned out properly and knowing that it has new bearings and gaskets would be fabulous man !!! I sure would hate to regret not having done so.
 

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the risk you take by just cleaning it out the best you can is that if you miss some metal or if bearings are already damaged, it will run when you put it back together but it won't last and you'll spend more money fixing it the second time. if it was mine i'd pull the crank, clean it, inspect bearing before it went back together.
 

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do it right

I am probably going to tear it down but before I do I am going to my favorite local shop to see what they would charge if I were to bring the motor by itself into them (just to be certain that it is done right). If they want too much then I will do the deed personally. - Thanks for being stern with me with your wisdom. I have learned the hard way before between my bull headedness and trying to save a few bucks. I was taught many years ago to do it right or don't do it at all. Why go against something that somebody spent their time teaching you ? - Thanks again...
 

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update: turned out to be a crank bearing missing a ball

I found the cause of the noise that I described. It turns out that it is a crank bearing that is missing at least one ball. I was able to see it thru the hole in the crank with my mini mag light as I turned it by hand with the cylinder removed. I sure am glad that I didn't try to just replace the top half.
Thanks for the tips fellas, it looks like I'm going deep on this one for sure now.
- Scotmo...
 
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