pay your respects - 23' YZ250 engine failure

maxer
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1/23/2023 3:11pm Edited Date/Time 1/23/2023 3:13pm

rip1 0.jpg?VersionId=W6C6pLwxlz8ghr 22 hours running c12/pump 40:1 motul 800. RIPimage-20230123171208-1  

 rip2

 

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Chatmore
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Memphis, TN US
1/23/2023 3:16pm

Dang dude. That sucks. On a ‘23?😳

Timo
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Wichita, KS US
1/23/2023 3:19pm

Ring gap isn't supposed to be in the front, did the locator pin fall out?

zehn
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Anchorage, AK US
1/23/2023 3:24pm

f

3

The Shop

ADynes
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IN US
1/23/2023 3:28pm
Timo wrote:

Ring gap isn't supposed to be in the front, did the locator pin fall out?

Looks like the ring broke there

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NSP139
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Temecula, CA US
1/23/2023 3:48pm

Cracked piston?

2
crmx105
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Dunnellon, FL US
1/23/2023 4:54pm

Could be mistaken but dont think the ring end gap is on the front side of the piston? I believe the 84 CR 250 did and it had a hugh exhaust port with no bridge so that bike had problems! Lol

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SEEMEFIRST
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Arlington, TX US
1/23/2023 4:55pm

They put the slug in bassackwards?

How many hours?

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crmx105
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1/23/2023 5:01pm
maxer wrote:
22 hours running c12/pump 40:1 motul 800. RIP     

rip1 0.jpg?VersionId=W6C6pLwxlz8ghr 22 hours running c12/pump 40:1 motul 800. RIPimage-20230123171208-1  

 rip2

 

Stock jetting and straight C12?

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Cygrace74
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Westport, MA US
1/23/2023 5:07pm
crmx105 wrote:

Stock jetting and straight C12?

He says right in the post half C12 half pump 

2
sandman768
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Saratoga Springs, NY US
1/23/2023 5:10pm

Need to see piston with cylinder off… to inspect ring locator pin … plug photo wouldn’t hurt either…

2
brocster
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Aliso Viejo, CA US
1/23/2023 5:33pm

To me it looks like a head gasket leak is what caused the sequence of events meltdown. 7DAEE63A-8127-40FF-9B94-4338BB5514B5

 

9
crmx105
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1/23/2023 6:15pm

I am GUESSING there is no further cylinder damage than shown so i would think there would be more on the back side if the pin came out but you never know??? LOL

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crmx105
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1/23/2023 6:32pm

You are most likely right. The piston will tell the story. 

1
crmx105
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1/23/2023 6:56pm

Yes it does! Had a new 02ish YZ 250 grenade a piston one time. No pieces of the piston left bigger than a nickle. Rolling to a stop it sounded like i had something caught in my front spokes. The noise ended up being the wrist pin and rod causing mayhem! LOL

mikenovel
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Corona, CA US
1/23/2023 6:56pm

WTF!!!!

He posts this....we have all this response to it, (minutes/hours later) but still no replys from the original poster?!?!

4
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Yz229
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San Diego, CA US
1/23/2023 7:02pm

Looks like lean detonation. What was your jetting?

7
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JK BRO
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1/23/2023 7:14pm Edited Date/Time 1/23/2023 7:14pm

The engine didn't fail. C12/Pump w/stock compression, running lean ruined that engine.

No way that motor wasn't knocking like a solar salesman.

7
1/23/2023 7:22pm

This was not a detonation problem. 

Something got loose/broke and caused that.

Your fuel choice is just fine.

3
5
MotofactioN
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Gloucester, VA US
1/23/2023 7:36pm
mikenovel wrote:

WTF!!!!

He posts this....we have all this response to it, (minutes/hours later) but still no replys from the original poster?!?!

Dudes probably wrenching on it. Or went to bed in disgust after posting this. Relax.

7
WarrenMX
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San Clemente, CA US
1/23/2023 8:11pm
mikenovel wrote:

WTF!!!!

He posts this....we have all this response to it, (minutes/hours later) but still no replys from the original poster?!?!

4th post in 12 years... this one really got you fired up Laughing

maxer
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1/23/2023 8:45pm
sandman768 wrote:

Detonation meltdown?

thats what my motor guy said, probably due to bad pump gas. i wasnt running race gas until recently

maxer
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1/23/2023 8:50pm
Yz229 wrote:

Looks like lean detonation. What was your jetting?

running lean may of been a contributing factor as well. I didnt change my jetting once it got a little colder due to my ignorance. i havent been on 2 strokes in a while and thought since it was running great i didnt need to mess with it - i was wrong! 

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maxer
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1/23/2023 8:54pm
sandman768 wrote:

Need to see piston with cylinder off… to inspect ring locator pin … plug photo wouldn’t hurt either…

i'll try to get some more photos, i dropped it off with someone much smarter than me on this stuff

Yz229
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1/23/2023 8:56pm
Yz229 wrote:

Looks like lean detonation. What was your jetting?

maxer wrote:
running lean may of been a contributing factor as well. I didnt change my jetting once it got a little colder due to my ignorance. i...

running lean may of been a contributing factor as well. I didnt change my jetting once it got a little colder due to my ignorance. i havent been on 2 strokes in a while and thought since it was running great i didnt need to mess with it - i was wrong! 

That's usually what happens. Exhaust side get's very hot when lean, causing detonation. (sometimes not noticed). Finally melts/explodes on exhaust side and piston/ring debris enter the chamber at wide open causing a lot of the damage you are seeing. 

What was jetting, altitude and temp?

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1/23/2023 9:47pm
JK BRO wrote:

The engine didn't fail. C12/Pump w/stock compression, running lean ruined that engine.

No way that motor wasn't knocking like a solar salesman.

“Knocking like a solar salesman.” I’m using this.

lostboy819
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1/23/2023 9:52pm
sandman768 wrote:

Need to see piston with cylinder off… to inspect ring locator pin … plug photo wouldn’t hurt either…

maxer wrote:

i'll try to get some more photos, i dropped it off with someone much smarter than me on this stuff

Bummer for you no matter what, feel bad because most of us have had something happen at one time or another, sucks thats its a new bike. Sad

3

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