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2008 yz250f engine lock up

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Hey guys, i just bought a 2008 yz250f. I only rode it 3 times and i believe the motor has locked up. I rode it all day yesterday and it ran perfect all day with no problems. Brought it home today and pressure washed it off cause it was covered in mud. Started it up and took it around the block and it kept dying randomly. i can't really say when for sure it was dying cause i wasnt paying that much attention. However, i believe it was whenever i would pull in the clutch and was running low rpms. They bike would idle fine. So i put it away for a couple of hours and decided to try it again. when i was about half way around the block it died and then the kick start was just stuck, like it was locked. They bike has around 50-60 hours and has never been apart. Do anyone have any ideas? thanks guys

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You just washed it right? May sound dumb, but do you still have the butt blug in the exhaust or a plastic bag over your air filter?

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If the motor is seized then its a strip down. Was the oil ok? Let it cool, take out the spark plug (clean inside the cover with compressed air first) and see if it has definately locked up.

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No :/ i didnt have the plug in or a bag in the filter, i have never done either of those things with my old bikes.

Yea oil level was fine. if there was water in the spark plug, i would at least be able to turn in over by kicking it wouldn't I?

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No :/ i didnt have the plug in or a bag in the filter, i have never done either of those things with my old bikes.

Yea oil level was fine. if there was water in the spark plug, i would at least be able to turn in over by kicking it wouldn't I?

Reason for blowing out the cover first is so when you lift out the plug, the contents of the recess doesn't fall into the cylinder. :confused:

Yes..you are correct. Water around the boot will not prevent the motor from being turned over. Plug out = no comp = easy to turn over. You will notice any tight spots a lot easier. :thumbsup:

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okay i will give that a shot. if it is seized up. what would need replaced? this is probably a stupid question but it wouldnt have dont any top end damage correct?

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okay i will give that a shot. if it is seized up. what would need replaced? this is probably a stupid question but it wouldnt have dont any top end damage correct?

How long is a piece of string......................

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How do you prevent water from getting on your air filter when washing the bike? If it wasn't covered in some way (plastic bag or air box cover) and you started it right away, you sucked water through it into the carb and engine.

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"j_bever" I'm not sure what kind of bikes you owned previously, but motocross bikes have extremely vented air box's. When you wash the bike with the filter in, the filter will get absolutely soaked. You either need to remove the filter and install a air box cover whenever you wash the bike, or put a bag around the filter when washing the bike. Then of course after your done, Clean/Dry/Oil/Install new air filter.

If I had to guess, I would guess that water was being sucked into the engine from the soaked filter and washed the oil off the cylinder walls, after a few min you have a damaged piston and cylinder.

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okay, thanks intensem1rider. i guess i just thought i would be okay because when i installed my new filter, i saw they was a box around the bottom and sides.

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well you you have a few possibilities

1. wristpin

2. rod bearing

3. crank bearing

4. timing chain in a bind somehow

and there are a few others but these are the most common. i would say that the rod bearing is the most common problem

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okay, thanks intensem1rider. i guess i just thought i would be okay because when i installed my new filter, i saw they was a box around the bottom and sides.

Hmm....such is life :thumbsup:

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