Crankcase breather tube

Wiz I am not doubting you,but I have to ask this. Before you took off your cam cover did you wipe under the frame and surrounding areas?,Taking off the cam cover is a little tight and if it is not clean all around,it is really easy to knock dirt in. I never did have dirt around the cam towers etc,but I did find 2 specs of fine dirt at the top of the vent tube.

It's a worthwhile question. I am pretty careful when working on stuff and while a speck or two of dirt might inadvertantly get knocked in/on something never would it amount to this much and so localized. The breather tube itself had the dirt in it also.

Hey I copy that,I don't blame you for concern.

My '06 sucked sand into the valve cover when I rode until I installed a filter. Some of the dirt even made its way to my oil filter. That is a 100% true statement. I dont know the math behind it, nor do I care to. I do know that a filter on the end of the hose stopped it.

Checking my valves the other day I saw that I had sand and dirt down inside this area (where the breather goes to). As I looked down inside, I noticed that I could see the valve stems and guides but no oil in this area. I figured, strange but maybe it was normal? I rode the next day for 4 hours in 100+ degrees temps and it ran fine.

Still worrying about this I started checking around and no one else had experienced this same thing (maybe they don't check thier valves?) I even went as far as contacting Jody Weisel at Motocross Action Mag. He actually met with Yamaha R&D about it. They had a small instance of this on one of thier test bikes that had been down many times. They believe the dirt travels up the tube when the engine is off. Yamaha suggests using a small filter at the end of this tube to prevent this from happening again. They also mentioned that I have to take the entire head apart and flush everything really good. They think that the sand could migrate down the valve guides and cause major problems.

Does anyone have any cleaning techniques they would like to share with me so I don't have to take the entire head apart? I guess I could change my timing chain but I would rather not till after this next season.

What I am also wondering is this: how many hammerheads are out there that don't do any maintenance that are out there riding thier bikes "guilt free" not even knowing what they have inside their head? Sometimes I think I find stuff that I shouldn't be looking for...Anyone else feel that way?

Like I said, I found grains of sand under my valve cover when I checked the valves. I even found sand particles in my oil filter. I use a reusable oil filter and I rinse it in a glass jar so that I can see what/ if anything is in the oil and trapped in the filter. I am not talking about just a few grains of sand.

It bothered the hell out of me and you can probably use the search function to find my original posts about it back from '06. I replaced the stock black hose with a clear hose so that I could see what was going on. After a day of hard riding, I could see grains of sand stuck to the inside of the hose all the way up to the valve cover. That settled it for me.

I now run a crankcase breather filter on the end of the hose. It is a filter just like pictured above that can come from any auto parts store. The problem was solved and I never saw sand in the engine again. That was nearly 100 hours of ride time ago and my bike is fine. I took the chance and never tore it down and had no problems.

This is not my first Yamaha. I have owned an '01 and an '04. I cehck my valves often and this was the only bike of the 3 to ever have any grains of sand work their way up to the engine.

i run a k&n crankcase breather, works awesome. also thinking of running a carburetor vent filter. i notice dust particles inside of the vent hoses

Very informative thread guys thanks. I was getting ready to do a similar mod to my yfz450, then i went and traded my fourwheeler for a thumper. So I have a 05 yz450f and the breather tube i think* goes up out of the head and is routed down the frame popping out almost at the bottom. I had just purchased a little k&n like filter that was made for breathers, Is there a certain way that i have to route it to not have the hose fill up with oil residue? From what i've seen people are putting inline T's in their hose and out the bottom of the T they have a small oil trap then they run the additional hose all the way to inside the air box. Can i run this without the "T" and the oil trap just straight through the breather to the filter? also does it have to go into the air box? Kinda a newb here with the dirtbike i was also wondering if anyone had a good picture of the routing or a tutorial maybe? Thanks a lot guys :thumbsup:

here is how i had mine set up before, but having it in this area vented all the fumes from the crankcase uptowards me and it always smelled like oil

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this is where it is now, i dont have to smell it anymore

006-2.jpg?t=1219454374

dont know if this will help you or not

Yes this did help a little bit. So from looking at the picture it looks like you ended up routing it into your air box? at least i'm pretty sure thats where i was. Did you have it routed up right under your seat before? thanks

beore it was next to the cam cover under the fuel tank

I don't doubt any of you finding dirt inside the cam area from the vent tube. I pull my cover every 3 rides. Not once did I find a spec of dirt inside,not even the ALUMINUM TUBE on top of the cover. I must have checked at least about 15 times. I had it routed the stock way and for the last 5 rides I routed it through the engine mounts down the right side of carb sweeping to the left side of carb and through the bracket for the carb vent hoses on top of the case. I checked after my first ride and went 4 rides purposely to see if dirt entered,NOTHING. I do believe it can happen,I just take my vent hose off every other ride and rinse it out.

Where I do find it dusty is in the sparkplug chamber,which is normal.It must come through the DRAIN HOLE on the right side of the cylinder or from washing the bike.The sparkplug cap has a really good fit on top of the cam cover,I cant see dirt entering there from washing. I know the cam cover gasket seals the sparkplug compartment,but it still bothers me.

Ok thats kinda what i was thinking it was. So did you pretty much just cut the tube so that it was about 6 inches long out of the cam cover. and just tied it up right there?

I don't doubt any of you finding dirt inside the cam area from the vent tube. I pull my cover every 3 rides. Not once did I find a spec of dirt inside,not even the ALUMINUM TUBE on top of the cover. I must have checked at least about 15 times. I had it routed the stock way and for the last 5 rides I routed it through the engine mounts down the right side of carb sweeping to the left side of carb and through the bracket for the carb vent hoses on top of the case. I checked after my first ride and went 4 rides purposely to see if dirt entered,NOTHING. I do believe it can happen,I just take my vent hose off every other ride and rinse it out.

Where I do find it dusty is in the sparkplug chamber,which is normal.It must come through the DRAIN HOLE on the right side of the cylinder or from washing the bike.The sparkplug cap has a really good fit on top of the cam cover,I cant see dirt entering there from washing. I know the cam cover gasket seals the sparkplug compartment,but it still bothers me.

I read over and over in different threads on different sights that say "i have never had this problem" but it only took a few people that said they did have a problem with it and had a blown motor from it that i thought well hell i guess its a really easy 15 dollor prevention if its not going to make the bike perform poorly. Very cheap insurance. I don't want to find out the hard way that it can happen

ya thats where it was, but now its in the air box

Alright thanks!!!

here is how i had mine set up before, but having it in this area vented all the fumes from the crankcase uptowards me and it always smelled like oil

023.jpg?t=1219454464

this is where it is now, i dont have to smell it anymore

006-2.jpg?t=1219454374

dont know if this will help you or not

What do you do with the little K&N when you jet wash your airbox, do you cover it or anything ? also do you have the part number for the filter so I know which size to buy to fit on my breather hose. Thanks

its a 1/2 nipple on the filter. u can remove the filter if u pressure wash your air box. just plug the breather hose with a bolt or something

hey man. I bought mine right in town at Schucks. it was a female piece to fit onto the filter but they also had a double ended male there that fits into the hose and into the filter. $10 for the filter and $3 for the double male.

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