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YZ250 coolant leak

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Hi everyone, I have a 2002 YZ250 2 stroke that has recently had its top end replaced (within past 6 hours of riding).  After taking it out of the garage to run it, I kicked it over and noticed a coolant leak coming from the cylinder base gasket towards the exhaust port.  It had no problems prior to this.  Two rides previously it may have been flooded by water a little; however, after a new spark plug and oil change it ran just fine again for another ride.  What is your opinions?  Should I change the base gasket, rebuild the top end again, or is there a simpler solution that i am missing?  Thanks.

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1 minute ago, Bradley Evans said:

Wiseco rebuild kit and gaskets

Get an OEM and 2 new o-rings and just do that. I don't like the paper gaskets just for that reason. 

Also, make sure to torque to spec and criss cross pattern. 

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2 minutes ago, P84ONE said:

Get an OEM and 2 new o-rings and just do that. I don't like the paper gaskets just for that reason. 

Also, make sure to torque to spec and criss cross pattern. 

Thats what I'll do but I'll probably disassemble the bike and let a shop put it on for me.  Do you think that the little bit of water that got into the engine may have played a role in this, and given that, should I put a new piston in?  When I start the bike the leak is a steady drip off the bottom of the bike.  Thanks!

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46 minutes ago, Bradley Evans said:

Thats what I'll do but I'll probably disassemble the bike and let a shop put it on for me.  Do you think that the little bit of water that got into the engine may have played a role in this, and given that, should I put a new piston in?  When I start the bike the leak is a steady drip off the bottom of the bike.  Thanks!

Are you sure it is comming from the base gasket and not the weep hole?

Please, don't let a shop do it, it is a simple job and you will love your wallet better.

No way of telling if it's in the cylinder and crank housing until drained and inspected.

We are hear to help. 

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1 hour ago, P84ONE said:

Are you sure it is comming from the base gasket and not the weep hole?

Please, don't let a shop do it, it is a simple job and you will love your wallet better.

No way of telling if it's in the cylinder and crank housing until drained and inspected.

We are hear to help. 

Yes! Clean everything dry super dry! Fire up with great light and look! I just did a crank and forgot to tighten the upper cross over and thought I was screwed, nope a weak clamp will do it! 

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16 hours ago, Bradley Evans said:

Do you think that the little bit of water that got into the engine may have played a role in this, and given that, should I put a new piston in?

If you are worried about some coolant getting in your crank case and running through the bottom and top end, then don't be.  You can drown a 2 stroke under water and get it going pretty easy (empty carb, cylinder/case and air filter) and if you ride it soon, it'll be totally fine.

BTW: Check your radiator overflow hose is healthy and routed correctly. I've seen coolant near the front of my cylinder base and found it can from the overflow. Base gasket was fine.

Edited by numroe
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