2009 YZ450 Oil Tank Breather Hose joint leaking

So this joint is loose and is leaking oil from engine. This joint attaches to the oil tank breather hose. I can freely push it in and remove the joint from the engine.  What holds this joint tightly into the engine? Why is it coming loose and leaking oil when riding? I cant find anything in a owners manual either. The same joint is right by the dipstick....on my bike this one is solid and i cant move it. The hose goes between these two joints. Yes, i have the clamp that attaches the hose to the joint, but i removed it so i could take off the joint. Anything will help! Thanks guys





Edited by brandon4d

The hose barb is a press fit into the case.  The part can be replaced, and the new one should fit tighter.


To correct this problem using the existing part, start by finding a bolt, drill bit, whatever, that fits inside the sleeve that presses into the case.  With this rod in place inside the fitting, make a couple dimples in the outside of the sleeve with a chisel or center punch point. That will raise the metal around the punch marks so it fits in the case more snugly.  You will need to apply a good non-hardening sealer such as Permatex #3 Aviation Grade when installing it, or the same staking you did to tighten it will cause it to leak.

Awesome, thanks for the help. I did end up doing some research and found out that Yamaha recommends buying a whole new case since its a press fitting. Screwwww that haha. I ended roughing up the case and the fitting with some sandpaper and put on some JB Weld High Temp epoxy. Hopefully it works....i have nine more hours until it sets. Why do u recommend none hardening? Do u think my choice in JB Weld High Temp epoxy putty was a bad idea haha?


Edited by brandon4d

Yes I do, because in the admittedly unlikely event that something else happens to it, you won't be able to get it back out gracefully. 


Non-hardening sealers work better in an application of this kind.  That's why.

I wanted to update this so readers with the same issue know what NOT to do vs what to do. So as you can see above, I ended up using JB Weld High Temp Epoxy. The only issue with this was it didn't make a perfect seal around the fitting ( part number 5XC-15373-00-00 , Pipe, Breather ) . I was getting a slow leak, so I had to bust out the chisel and knock all the JB weld off.....that was a pain in the ass! Anyways, I tried some different non-hardening sealers...but those didn't provide enough shear/tensile strength. After hours and days of research, I found what I was looking for though!!! Loctite 680! Loctite 680's intended use is for worn out press fittings..do some research to make sure this is def what you want. A little about 680... Fix cure time 10 minutes and full cure time 24 hour at the temperature of 77 degrees fahrenheit. 0.15 maximum gap fill. Mild odor/scent. Brake fluid, motor oil, unleaded gasoline resistance. 4000 psi shear strength. 1250.0 cP viscosity. Make sure you have it in place where you want it....its not coming out once cured haha. Notice that it says 0.15mm maximum gap fill....I wouldn't say that's 100% accurate, if you go to loctites TDS ( Technical Data Sheet ) it says different. Good info though, read into it http://tds.loctite.com/tds5/docs/680-EN.pdf .

Point of my rant is, I followed the directions and read the TDS for Loctite 680 and it worked wonders. The press fitting shows no signs of leaks after several hard rides, to include racing the Clovis Kicker Arenacross. I wouldn't use anything else and I wish I would have done more research on day one.

I know you may be thinking that maybe I work for Loctite and I'm pressing the product....but I assure you I do not. I only want to help those that may fall victim to this pain in the ass incident. If you have question please let me know as I will try my best to answer them. Stay safe and ride on!

Edited by brandon4d

You are my idol right now man I could not find anything on any sites about this I don't know how you found out all this information I'm gunna try this out on my 2007 yz450f!

Not all heroes wear capes !!

Good stuff man. I hope it's working just as good as it worked for me. Mines still holding up.

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