YZ 250 coolant leak

hassbeen
I replaced the cylinder on my YZ 250 2012 model a few weeks back due to a huge blow up. The cylinder split in half, but that chapter is over.
The bike was bought used, so I don't know the history, but the head nuts were not domed, but normal nuts as used on the Cylinder base.
Prior to the blow up there were no leaks on the head,however after installing the new cylinder and fitting the existing head , coolant escapes out of the head out of all six studs? Weird I know. They are torqued correctly and have the copper washers on.
Any thoughts?
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Tryhard
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Tryhard 6/13/2017 4:40am
6/13/2017 4:40am
I would find some way to flat line the cylinder head to see how true it is ... could be warped ... lean mixture causes intense heat... being as u don't know the history .. im no mechanic nor wiz ... I would definatly give it a good cleaning and inspect for cracks from being over torqued ... and also locate the proper bolts ... and use those ..

My 2 cents
Acidreamer
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Acidreamer 6/13/2017 6:10am
6/13/2017 6:10am
Is there any burs or dirt holding them up enough to allow them to leak? are the copper washers new or the correct ones? What about the nuts? Are those indeed the correct ones and not dirty or have burs?
hassbeen 6/13/2017 7:04am
6/13/2017 7:04am
Acidreamer wrote:
Is there any burs or dirt holding them up enough to allow them to leak? are the copper washers new or the correct ones? What about...
Is there any burs or dirt holding them up enough to allow them to leak? are the copper washers new or the correct ones? What about the nuts? Are those indeed the correct ones and not dirty or have burs?
No dirt or burs, but they are not new, also nuts weren't correct ones, but they didn't leak before which is confusing.
I've ordered new nuts and washers. I was just curious as I couldn't figure it out why all 6 would leak.
Hondas4Life3
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Hondas4Life3 6/13/2017 10:33am
6/13/2017 10:33am Edited Date/Time 6/13/2017 10:38am
Those copper washers need to be replaced every time you take the head off. They are crush type. New head gasket and new copper washers should be the answer. Check that the head and top of cylinder is straight if possible. Also some have acorn nuts to go on top of the studs, could be possible you have the wrong nuts as regular nuts will leak.

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ehr400
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ehr400 6/14/2017 9:20am
6/14/2017 9:20am
Have to have the acorn nuts or other wise coolant will weep up from the threads.
hassbeen 6/15/2017 2:13am
6/15/2017 2:13am
Hondas4Life3 wrote:
Those copper washers need to be replaced every time you take the head off. They are crush type. New head gasket and new copper washers should...
Those copper washers need to be replaced every time you take the head off. They are crush type. New head gasket and new copper washers should be the answer. Check that the head and top of cylinder is straight if possible. Also some have acorn nuts to go on top of the studs, could be possible you have the wrong nuts as regular nuts will leak.
Thanks guys will let you know after replacing the nuts & washers
hassbeen 6/15/2017 2:19am
6/15/2017 2:19am
How do I check the head for warping damage?
Tryhard
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Tryhard 6/15/2017 2:56am
6/15/2017 2:56am
hassbeen wrote:
How do I check the head for warping damage?
Use something as a straight edge , a fabricators square something thats pretty straight and lay it flat on the mating surface of the head and cylinder... this is if you dont have dial indicators... but with the method stated you shouldent see any gaps in the mating surface and the straight edge... no this is not 100% accurate but its good enough..
RockyRider
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RockyRider 6/15/2017 10:57pm
6/15/2017 10:57pm
hassbeen wrote:
How do I check the head for warping damage?
Get a piece of 220 sand paper, put it on a flat surface (marble, glass etc) and rub down the head on it. It will be obvious if it's warped after a couple passes.
Tryhard
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Tryhard 6/15/2017 11:11pm
6/15/2017 11:11pm
hassbeen wrote:
How do I check the head for warping damage?
RockyRider wrote:
Get a piece of 220 sand paper, put it on a flat surface (marble, glass etc) and rub down the head on it. It will be...
Get a piece of 220 sand paper, put it on a flat surface (marble, glass etc) and rub down the head on it. It will be obvious if it's warped after a couple passes.
also another good old school method... always more then 1 way to skin a cat...

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