Broken Engine

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S

Stygian

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So I don't know what caused this but I fired up the MT today it ran for about 30secs then shut off went to start it again and it was stuck pulled the engine apart and this is what I got, lol. If anyone has any ideas on what could've caused this please do share, also would it be better just to replace the whole engine or rebuild this one?


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A bent rod is probably the culprit. Once bent, it is weak, like an aluminum can once the side is dented. However, if you run it really lean, the piston can seize. Also, the engine should warm up a bit before any hard runs. Aluminum expands alot quicker the steel. It is possible it siezed due to improper warm up, ie, piston expanded quicker then the cylinder thus causing siezure.
 
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MrMeatHooks said:
A bent rod is probably the culprit. Once bent, it is weak, like an aluminum can once the side is dented. However, if you run it really lean, the piston can seive. Also, the engine should warm up a bit before any hard runs. Aluminum expands alot quicker the steel. It is possible it siezed due to improper warm up, ie, piston expanded quicker then the cylinder could expand causing siezure.
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That's probably what happened, I tend to forget to warm up the engine before wot LOL, oh well gives me a good excuse to upgrade and when I showed the wife she's like ok and didn't say anything else.
 
Looks like a cold seize. This COULD happen IF you were heavy on the throttle before warming up properly. The piston and cylinder expand at different rates as they warm up. This causes the piston to stick in the bore and bend the rod. Just one thought. I am giving ideas. I don't know what rpm it locked up at.

Did you clean your engine before taking pics? The ports and spark plug look very clean. How many hours on engine?
 
GRIPNRIP123 said:
Looks like a cold seize. This COULD happen IF you were heavy on the throttle before warming up properly. The piston and cylinder expand at different rates as they warm up. This causes the piston to stick in the bore and bend the rod. Just one thought. I am giving ideas. I don't know what rpm it locked up at. Did you clean your engine before taking pics? The ports and spark plug look very clean. How many hours on engine?
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I think that is exactly what happened, my bro came over and wanted to show him how it sounded with the upgrades and I didn't let it warm up. I did not clean anything before taking pics, The engine has no more than 5hours on it if that at all, I have only put maybe 2 tanks through it and that's including actual play time and just starting it up and tinkering.
 
I asked because a spark plug with some time on it will/should be a golden brown color on the tip and porcelain.

It is hard to give advise without seeing the engine or knowing you. Maybe the lighting makes that plug look extra clean.
 
GRIPNRIP123 said:
I asked because a spark plug with some time on it will/should be a golden brown color on the tip and porcelain. It is hard to give advise without seeing the engine or knowing you. Maybe the lighting makes that plug look extra clean.
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The spark plug has only one start up on it that's why it looks so clean and it was when the engine seized up.
 
love the new air filter and the 990 carb is amazing, haven't gotten to test the new aluminum parts to see how they hold up compared to the plastic ones, soon as I get the new engine and it's running, I'm hoping to take it out.
 
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