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Bottom end troubleshoot

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I recently purchased a 1997 Honda Cr125, i was riding Monday when all of a sudden I lost all power, it bogged and then stalled and would not start .. before hand I have done all general maintenance (clean carb, new filter and oil.) so I took the top end apart right away and found my piston got mangled by what looked like a piece of spark plug or rist pin.. the cylinder has a deep score down the side all the way from top to bottom  from the mangled piston ring also. So I have the cylinder out to get machined to stock bore and of coarse will get a top end rebuild kit .. what my worry is, is the bottom end ... I checked my connecting rod and as I turned it I noticed tiny little metal fragments on the crank shaft not many but some, also there is lots of left-right play but very little up and down with my connecting rod. I drained my oil and checked my magnetic drain plug and noticed more tiny metal fragments. I'm wondering how big of an issue these fragments are as I would rather avoid taking apart bottom end and paying a lot more ... and also how much left-right play is the connecting rod supposed to have ?

All opinions appreciated !!

Edited by Staucher

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I would maybe split the bottom end and check everything just to be sure and so if anything is wrong it won't cause a problem in the future and cost you lots of money

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The oil you drained is the gearbox lube, not related at all with any debris that might be in the crankcase. 

(2-strokes share the outer cases but have separate internal cavities for engine & gearbox)

 

The fact the connecting rod has any up/down play alone warrants to split the cases and fix that,

since your engine also suffered a severe failure, no doubt some debris made it's way in the bottom as well.

 

Full gaskets & seals kit, cylinder re-plate, new piston & ring, perhaps a rebuilt crank + tools + labor if required.

Even with a fully rebuilt engine it's still 20 year old bike around it, you decide if it's worth investing a lot in it.

 

Edited by mlatour
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strip it - any play at all like youre describing could turn into a catastrophic failure if you dont

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Rip it apart. Metal and two strokes don't get along well. Everyone likes to say that side to side play doesn't matter, but it does. It is directly related to the up and down play. If you're questioning the up and down play and there is an odd amount of side to side play, your crank is shot. What brand of crank?

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