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WR250F -17 hole burned to breather tube by header pipe

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had a long almost 4hr ride in muddy and wet conditions. got a lot of mud from frot wheel on engine and mud pushed breather tube against exhaust header pipe and hole was burned to the breather tube. 

So - I got some muddy water under the airfilter and into engine, sand in inlet and throttle body + muddy water into cranck case. (water was in the breather pipe when throttle open, but when throttle closed, no suction, and water (and mud) flows into crank case) 

Engine stopped, connection rod bearing seized.

Engine needs New piston and rings, cylinder honing, new connection rod, new oil pump, couple of bearings to tranny etc. - not fun.

In case you have a WR250F 2015 - 2019 It’s worth to check routing of the breather tube. I had it routed and clamped how it should be but still mud pushed it against exhaust head pipe. It’s a good investment to put couple of extra cable ties to make sure the breather tube is secure, specially, if you have an aftermarket headpipe with larger dia reducing clearance (I have ackrapovic head pipe with xtra chamber)

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That's a brutal outcome. I've got an FX and will check the routing to ensure this risk is mitigated. Good luck with the repairs.

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Could you post pictures of the damage I’m not sure what breather you are referring to! Were you using the stock skid plate, no skid plate or an aftermarket unit?

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Wow, colossal bummer, and such a weird way to destroy an engine. How much larger is your head pipe than stock?

Thanks for sharing the warning.

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Could you post pictures of the damage I’m not sure what breather you are referring to! Were you using the stock skid plate, no skid plate or an aftermarket unit?

IMG_4574.JPG

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enska_kuski, thanks for the warning on this.

I have a 2018 WR250F.  I am new to dirt biking and small engine maintenance, so this piqued my interest into a few more details.  If I am missing something, please correct me; thanks.

Yamaha parts diagram calls this part “pipe breather 3”; my owner’s service manual calls it “cylinder head breather hose”.  I have attached a picture of mine; my bike has the stock header; this picture is taken from the left side of the engine.

I measured the distance between the header pipe and hose at the closest point; it is 20 mm.  Even taking away 1/4 of that distance (per enska_kuski) does not leave much space.  I looked how I can further secure it with zip ties per enska_kuski suggestion…the only way I can see is to wrap the tie around the frame.  Any other suggestions?

yama_1.jpg.b05fdc28172facfe1f7571a06669b5bd.jpg

Edited by blt125230

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enska_kuski, thanks for the warning on this.
I have a 2018 WR250F.  I am new to dirt biking and small engine maintenance, so this piqued my interest into a few more details.  If I am missing something, please correct me; thanks.
Yamaha parts diagram calls this part “pipe breather 3”; my owner’s service manual calls it “cylinder head breather hose”.  I have attached a picture of mine; my bike has the stock header; this picture is taken from the left side of the engine.
I measured the distance between the header pipe and hose at the closest point; it is 20 mm.  Even taking away 1/4 of that distance (per enska_kuski) does not leave much space.  I looked how I can further secure it with zip ties per enska_kuski suggestion…the only way I can see is to wrap the tie around the frame.  Any other suggestions?
yama_1.jpg.b05fdc28172facfe1f7571a06669b5bd.jpg

That’s correct hose you have picked up. Zip tie wraped around frame would work ok. It’s also may be worth to check the clearance periodically, e.g when changing oil or washing bike. However, I had -15 and -16 model bikes, with same header and both bikes got around 130 hours without this issue.

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I have another warno for you all.  I took my WR46F to the Yamaha dealer for a valve check and general once over.  The next time I was out riding I smelled gas and saw "steam" coming off the engine.  The dealer had routed my fuel line wrong and it got against the header and burned through.  It's a miracle that the whole thing didn't go up in flames.  I had to do a McGiver fix in the middle of a mosquito infested swamp, but at least the bike didn't catch on fire. 

Check all your hose routings after any maintenance to make sure you have everything secure and adequate clearance to the header and any moving parts. 

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You guys need to block out mud from being able to enter the engine area above the stock skid plate.  One of the great features of this 14+ YZ250F models is the wrap around exhaust.    If you notice in this picture, I riveted a piece of plastic to the top of my skid plate.  It completely keeps dirt from entering the engine area unless it is a really muddy day and it comes in from the sides.  Great cheap mod!

IMG_1432.JPG

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That breather pipe is held close to the frame by a rubber hoop which it passes through..was yours not through this rubber hoop?

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That is a bummer! I zip tied mine to the starter wire after reading this even though I don't ride in mud very often and my skid plate (Hyde) covers that front portion.

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