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every wreck, oil saturates the plug

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Ok so i rebuild my sons 2007 CRF250r, crank and piston. Runs great..  But Now every time he lays it down oil saturates the piston making it really hard to cranks, not to mention the the smoke.

Anyone Have any clue why it is doing this?  

 

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From what I know about four strokes it sounds like a cracked ring or a seal blown that could be letting oil above the piston. If it smokes when it runs and uses oil it could be a cracked oil ring

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Thanks,

I hope all the rings are good they only have about 2 hours on them.   It runs good no smoke while running, great compression.  

This only happens when it is laid over/wreck.  

I told him to just not wreck, but he didn't lesson.!! ha 

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It's fuel not oil, that's what the hot start lever is for

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OK.   When it does crank, it is a thick light blue smoke.    I pulled the plug and it was dripping.  It looked like oil to me but I didnt check real close.

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It could be oil from the breather system making its way into the carb when the bike is tipped, make sure the air boot has no oil in it and drain the breather hose.

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It could be oil from the breather system making its way into the carb when the bike is tipped, make sure the air boot has no oil in it and drain the breather hose.

+1 what he said! Oil comes out valve cover and makes its way to air boot. Stop crashing lol!

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+1 what he said! Oil comes out valve cover and makes its way to air boot. Stop crashing lol!

 

fail fail fail fail

 

The 250R doesn't vent the valve cover into the airbox = fail.

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Thats a 2007 crf250r airbox. you sir do not know what your talking about. = fail, fail, fail!

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fail fail fail fail

The 250R doesn't vent the valve cover into the airbox = fail.

You might have a "competition" bike that has the hose routing changed to not do so, but all OEM CRF valve covers vent into the airbox...

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fail fail fail fail

The 250R doesn't vent the valve cover into the airbox = fail.

Wrong.

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Here is what I found,    The one way valve between the cases broke.   I found the piece on the ignition side of the cases.

Why its broke I don't know,  it looked fine when I put the cases back together.

 

Its on page 243 of the Honda tech manu al

 

How important is this valve?

Edited by ronqqq

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You might have a "competition" bike that has the hose routing changed to not do so, but all OEM CRF valve covers vent into the airbox...

 

Neither my buddies 2005 nor my 2012 has it routed into the airbox

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Neither my buddies 2005 nor my 2012 has it routed into the airbox

Are they stock bikes, or have the vent systems been modified?

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Are they stock bikes, or have the vent systems been modified?

 

My 2012 is stock, his 2005 was an ex race bike.

 

I can see on the parts fiche the different connections, so I guess I have to apologize to iMOTO and let him make fun of me for not knowing WTF i'm talking about.

 

I will have to look into this, weird.

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You learn something every day, it's all good.

 

Maybe you do, I just keep making the same dumb mistakes over and over. At least thats what my wife says

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