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Discussion Starter #1
Please tell if what I heard is wrong. I heard that on a seized two cycle engine you can poor oil down the plug hole and work the piston out of its seize. Iam guessing this is wrong. This was on the subject of a YZ 125 that I recenlty ran the coolant out of and this is how it seized. Is it a different story with running it out of coolant opposed to running it with no oil or is it the same?
If what I heard was wrong (which I think is)
than what should I do with the engine? New piston, hone, or new piston and bore than hone. Thanks alot all of you I know you won't let me down.
 

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It is most definitely true that you can get your engine working again after a seizure by pouring oil down the plug hole. I've done it before and I'm sure to do it again before my two stroke days are over. If you ran out of coolant, the piston is likely to bind in the cylinder causing the seizure. If you run out of oil your situation is likely more terminal since the piston ring will eventually weld itself to the cylinder wall.
Other than out of oil seizures, I've had machines that have run out of coolant or have been jetted a little too lean (by choice or by component failure such as a blown base gasket or torn carb boot). Every time after a seizure though, sit tight (so to speak) for 10 minutes and try to pull/kick it over. If it turns over, chances are it will start and get you home to assess the damage and what kind of repairs you're in for.
A buddy of mine had a new Ski Doo 800 triple with a bad base gasket. Everytime he hit 80 mph the centre cylinder would seize tight. The plug would have little bits of aluminum on it from the piston! We would dip a screw driver into the oil resevoir and put 10-12 drops down the cylinder, pull it over a few times, swap the plugs around and fire it up. It would work great until he couldn't keep it under 80 mph. SQUEEEEEEK! We did this at least six times before we got home and he took it in for the warranty work. Funniest thing was, he even ran open water knowing the engine situation!!
 

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Well, it depends on how it siezed. If it's a 4 point seizure, you can probably just do that. If a skirt sticks, you are screwed. The skirt sticks to the cylinder wall, and when it sticks it cracks the skirt. 10 miles later down the trail, your piston will be in multiple SMALL pieces, and you will now need a top and bottom end rebuild. If you sieze it, PLEASE take off the head, intake, and exhaust and inspect the skirts for cracks. Your pocketbook will thank you. new gaskets = $40, rebuilding the bottom end = $300.

-Dean
 

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Yeah, I wouldn't chance causing more damage to the sled. I know though, if I break things, I break them good so there is no chance of recovery. [:)]
 

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Discussion Starter #5
So if I was too put coolant back in, inspect the piston for cracks, put oil down the plug hole, and kick it over a few times it would run just as it did before the seizure? How long can you go before you start to have problems, or does it depend? Thanks for all of the feedback.
Oh ya why should I pull the head?
And how do you break the sieze? (kick start or push start) or something else
 

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Yeah, it probaby will run. No guarentees.

More inportantly, is pull the intake and exhaust like I said, and look at the skirts.

If you don't do at least this, your pretty much setting $300 on a table and hoping the wind doesn't blow it off.

Oh, and to free it, just yeah, kick start it. You could get another 3,000miles out of it. You could also get 100 yards. If it's stuck bad enough to not kick, then you could try shoving a thicker wooden dowel down the spark plug hole, and hammering it. If it's still stuck, you will most likely break the piston free-ing it.

-Dean
 

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Discussion Starter #7
Sounds good. I plan to look at the skirts like you said initially. Thank you all
 

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my 400 siezed last year and we put oil down the cylinders and it broke free, but then we ran it for a few minutes and it siezed again. We took it apart and the cylinders were scored and the pistons were shot. Your best bet it to take it apart or risk causing more damage.
 

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Yeah, the best bet for you would be to just do it right the first time and same yourself ALOT of money in the end. Take your cylinder(s) off and take a good look at it. Usually when you run out of coolant and it seizes your piston is scored pretty good. Sometimes all it will cost is $100-$200. Oh and an other thing, get your crank checked to make sure its not warped or anything, just .015 inches off on your crank can do alot of damage, goodluck!
 

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I just did this with my sled last year and it seized up again after about 5 minutes. It was enough time to get to the truck though. Definatley a very short term fix. I am putting a new piston in right now.
 
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