MY new to me bikes, piston skirt shattered.

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Dec 18, 2002
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#1
Hi i just moved up to a 250, sold my rm125 and bought a 1996 honda cr250 in excellent condt(Or so i thought), i serviced the bike properly before i rode it, warmed it up properly, after about 30 mins of slow riding, the bike stopped, with a ting noise, i pulled in the clutch and costed to a stop.
Last nigh a pulled the head to see a piston with a smashed skirt, i could only find about 1/2 the smashed piston pieces, the spark plug was a grey/tan colour, which indicates lean condt right? The cylinder is perfect without a scratch. Why did this happen? Was the piston just too old? Where are the piston pieces? Thanks Im in shock here!!!! So please help.
 

biglou

#2
Same thing happened to a buddy's 99 RM250 two summers ago. You won't want to hear this, but you're most likely going to have to split the cases and find the missing pieces as they probably fell into the bottom end. New piston/rings and gaskets and you should be good to go if your cylinder is still in spec. Good luck.
 
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#3
I thought that, but guess what, i spent over two hours trying to remove the swingarm, no luck. Any other ideas?
 

jmics19067

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#6
the piston probably shattered because of too much clearance.

Another thing you're probably not wanting to hear but... the bike is 8 years old and you really don't know the true maintenance schedule from the previous owner. My suggestion at this point is to rebuild the whole bike,since "I" can't stand new problems arising without warning. I would get that swingarm bolt out bleed or blister and rebuild the entire engine with atleast new bearings everywhere then I would rebuild the complete rear suspension. That swingarm bolt should be snug not stuck , kinda tells me that there is a problem with that and who knows what else is a problem unless you inspect everything.

It would be cheaper and safer to repair anything that might be a problem now then to wait for something to fail possibly ruining a good part or causing an accident. Any particular questions search these forums and ask, also might be a great time to offer a mechanically inclined person in the neighborhood a beer. :thumb: