Why O Why Please NOOOO

Well it has finally happened . Piston failure ! But why did the Piston shirt break but the rings were still intact , and pretty much unharmed even after chewing one entire side of my piston skirt into tiny bits ? Maybe to many rpm ? The cylinder looks a little scarred but may be usable , maybe ? Anyone know where to get replacement DR pistons ? Will a Honda Metra Kit piston work with a lil dremel work ? Anyone have any input at all ?

IRE Rick

Correction

SAD

IRE Rick

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Oh yeah , The carnage . PICS

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another one

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Look how the skirt melted and turned into the head gasket .

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Holy shit! That sucks man!

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WHY why me , why o whyyyyyyyy . Oh god please nooooo.

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Offerings to the gods of speed...

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All that corrosion, youmust live near the ocean

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So... more details needed before we offer up full scale empathy. How old is this kit? How dialed in was your jetting? How did you get this to look like mice ate your piston?

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Dayuum!

I've seen pistons mangled but that thing shredded itself.

Sucks man, wish I could offer some advice.

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I.R.E. Mike Pee /

Mannn, that sucks.

Maybe 76,000 RPM was too much?

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Maybe some of that road salt snuck in there somehow? I doubt it though. You aren't running injector are you? It almost, at least to me, looks like you were ripping, and it got hot, you hit an icy puddle on half of your cylinder, and the metal constricted in the back and almost crushed/melded with your piston. Or not.

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You better figure on changing all the bearings in the engine.

Including the mains, and rod. That melted aluminum will get into everything.

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too much play in the big end of the connecting rod

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i'm with silverfox here, thats a full rebuild dude. i wouldnt just throw a new piston in there, bad news. sorry buddy.

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I've never seen anything like that before!!! That blows my mind. Sorry to hear that though... and good luck with the rebuild.

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Oh yeah , its a pretty freshly rebuilt nu50 with the 70cc DR kit that has been rocking for like 1000 mles . just made some mad variator changes and BOOM . Most power I ever had from this bike before the disaster . No good !!!!

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Downhill Harvey (OFMC) /

Reminds me of my Hobbit. What happened to mine was, previous owner used a B5HS insread of BP5HS, B5HS plugs are longer. The piston hit the plug electrode, broke off and mangled the piston and cylinder. It must have got stuck near a port and tore it up. Doe your piston top show a telltale electrode strike? My piston top had an indent that perfectly matched a plug electrode strike.

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That white stuff on the cooling fins is from time trials at the salt flats . NOT, Its just from a road underlayment , " minus " which is crushed stone . Not puddles of ice and water . Plus the rings and cylinder are in pretty decent shape yet . So not from a seizure . And Peter that con rod is a new bearing on the small end and a like new brass bushing on the big end . I cant see how that would make the piston skirt break off and then get pulverized on its way out of the exhaust .

I was asking about replacement pistons so I can save the cylinder with a good hone . The aluminum is way softer than the iron bore and so it is most likley usable again . Not because I wanna throw a piston in there and run it . I just dont get it . I dont deserve this crap . Rebuilding three motors all at the same time sucks .

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John Joedicke /

Wrong piston maybe. Too long a skirt and collided with the bottom end. To many projects maybe on the table at once!

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double , Its the right piston , I do have tto many projects going . Tho rather than that being the source for the failure , I belive that the piston hit the head at the bottom forcing the top of the piston in the skirt area "rear top , the part that broke " upward and caused stress fractures at the weakest point , "which is in the middle of the the boost port . After that the skirt broke off and subsequently chewed into tiny pieces before being passed threw the transfers and into the combustion chamber . There it was smashed even further before expelling out the exhaust port .

Long story short , Piston and the head dont play nice together. My head must not have been perfectly milled perpendicular to the cylinder . Which would have been ok if I maintained normal rpm . Everything stretches a little more when you speed up the rpm . My head had been running on this kit for its 2000+ miles lifetime . Hard Miles !!! Only afther I forced it to run well beyond its normal rpm s and operating capacity did it fail .

It Was MY BAD FOR SURE

Now I know

And knowing is half the battle .

IRE Rick

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Rick, I think Peter has the right idea.

I wonder if the bearing was worn down, and allowed too much play in the piston. this would allow the bottom of the piston to "Slap" against the cylander wall, breaking it down untillit finally gave out. How tight is that bearing?

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💀Kim Jong illest💀 /

holy balls. much condolences.

man, that motor looks like it was salvaged from the titanic.

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It only looks like that because the day earilier I went off road quite some way . Gravel and puddles and dusty roads quickly turned a clean , fairly freshly painted engine into what you see in the pictures .

The nu50 that I had completely torn down just prior to this disaster has exactly what your talking about . A totally worn and loose as a goose big end con rod bushing . The engine that ate my DR kit STILL HAS a very tight and smooth con rod bushing . No side to side play , and no back and forth either . I am getting a za50 and 2 nu50 cranks together to take to a local machine shop . Where they can be pressed apart for repair . Replacing brass bushings with needle bearings . Or roller bearings . I may even have to have the pins resized and or polished . Dont know how bad they will be until they are pressed apart .

Anyone got 26 ton press they want to give me ?

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