2015 ktm FE 250f CP piston how did this happen??

ktm-5
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5/14/2018 5:32pm Edited Date/Time 5/15/2018 3:15pm
OK a friend of mine had this issue with his oem piston at I think it was about 27 hrs on the piston. Any ideas how thus could have happened? A little background the bike was stock except fmf exhaust and a Ron Hamp port job and valves. We think we know what may have caused it but looking for others ideas.

Yes that is the chunk from the piston that I found when I replaced his tranny gears to the updated gears, almost in the tranny area
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CarlinoJoeVideo
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5/14/2018 6:21pm
Could it be detonation?

Could the piston have been hitting the spark plug?

Wrong base gasket after port job?
ktm-5
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5/14/2018 6:57pm
Definitely wasn't hitting the spark plug and was not the wrong gasket
Paw Paw 271
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5/14/2018 7:12pm
It look like the piston hit something. Maybe the small piece by the piston?

Paw Paw
ktm-5
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5/14/2018 7:18pm
The small piece is from the piston

The Shop

kb228
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5/15/2018 1:20am
Whats the CR & what gas was used
ktm-5
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5/15/2018 1:23am
kb228 wrote:
Whats the CR & what gas was used
CR?? I'm assuming you mean CP? That is the brand of piston, the gas used was vp pro6
omalley
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5/15/2018 1:55am
kb228 wrote:
Whats the CR & what gas was used
ktm-5 wrote:
CR?? I'm assuming you mean CP? That is the brand of piston, the gas used was vp pro6
CR=Compression Ratio
ktm-5
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5/15/2018 2:03am
kb228 wrote:
Whats the CR & what gas was used
ktm-5 wrote:
CR?? I'm assuming you mean CP? That is the brand of piston, the gas used was vp pro6
omalley wrote:
CR=Compression Ratio
Oh yeah duh....lol Compression is stock which is I believe 14:1
kb228
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5/15/2018 3:07am
Was it mapped for that gas? 95 oct oxygenated gas with that high of a CR i wouldnt be surprised one bit if it was detonating as others said. Add in the exhaust and youre running lean most likely.
ktm-5
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5/15/2018 4:16am
Could detonation just knock out a solid junk of piston? I always thought it would burn a hole through it not knock out a solid chunk, but I don't know I've never dealt with any issue like that which is why I'm asking here. When I first saw it I would have sworn it hit the plug but he said no it didn't, definitely weird for me to see. Lol The bike is a factory edition and came with the exhaust, I think, like I said it's not my bike, so idk if the factory had a different map for exhaust but it was not mapped for the pro6.
kb228
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5/15/2018 5:21am
I would think if theres a split in the crack, it could blow out the center part. Detonation/preignition destroys pistons.

Personally i think it hit the plug even tho your friend says it didnt
RCF
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5/15/2018 8:04am
Was the Piston installed backwards, it just seems weird there's so much carbon buildup on the intake valve side. There's also a lot of marks in the top of that piston like something was sucked through the motor , I'm assuming the piece fell down and didn't go up because you found it in the transmission.
walent215
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5/15/2018 8:58am
pic of the wrist pin? almost looks like the 06 kx450f wrist pin issues when those bikes first came out.
c0ncEpT
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5/15/2018 10:23am
Heat caused that. It melted and started the crack from there.

MX915
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5/15/2018 10:32am
Oxygenated fuel + flowed head (more air) + stock mapping = hot and lean?
ktm-5
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5/15/2018 3:15pm
I don't have a pic of the wrist pin. The piston wasn't installed backwards either. The only thing that was figured out to cause it was a lean issue. After he rubuilt it he took it to Hamp and put it on his dyno and it was 2pts too lean at top rpm and after 15 minutes of run time he would lose 4hp as the motor got hotter. Ron had said that his bike was running way leaner with the stock ecu than what mine ran on his dyno, so he is now ordering a vortex to fix the lean issue. That's what we believe is the problem but also idk if it had anything to do with it but his fuel pump also went out so maybe it wasn't pushing as much fuel as needed either.?.?

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