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TooFast

Best Breather Hose Filter???

10 posts in this topic

Decided to get smart and install a breather hose filter after reading some threads on sand in the motor....to save many of us some time, was hoping you guys could post some pics and part numbers/mfg of ones that have a nice fitting barb for the stock yammie breather hose. Took my hose to Wally Mart and they didn't have anything close to fitting. Was thinking the barb could stick out of the air box from the inside, push the hose on and cinch it with a zip tie. Thanks ahead of time

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I got mine from autozone. It is a valve cover breather for an older style motor. Just take your hose to your local automotive store and they will hook you up. My filter is similar to a K&N so I oiled it to help trap dirt. I mounted mine inside my airbox by screwing it to the airbox from the outside. There is a great spot on the right side. Make sure to put a "T" inline to vent the water vapor out. Run the T down by all your other vents by the swingarm. Run the breather hose over to the right side and slice the mud flap and poke the hose through. Its all pretty self expanitory once you get in there. Good luck.

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After much reading up on this subject I decided to purchase a K&N style filter with a 12mm adapter, this fits snugly into the stock breather hose. I plan on running this into my airbox by drilling a hole through the right hand side of the rubber mudflap which is riveted to the airbox, I don't plan on T'ing another hose down to where the carb breathers are yet, just going to run it like this and see how it goes, hopefully I won't have a problem. I have never had a problem running it stock so far (touch wood) and that is riding deep sand mx tracks, but as I plan to race H&H and Cross Country I have decided to go with this for peice of mind for river crossings and deep mud :lame: I am also going to run two of my carb overflows up there on the opposite side of the airbox if they will fit (not weighed this up properly yet).

Image011-1.jpg

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How would a T line work? wouldnt it be possible that the line you run down from the T would suck sand or dirt up too? And what would happen if you didnt T it?

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Assuming that both the upper and lower branches of a T'd breather hose exited in the open air, the lower on would not be able to raise sand or water into the engine. By splitting the line, the pressure or vacuum in either tube would be half of what is present in a single hose, and as soon as the end of the lower hose was submerged in anything, the air would take the path of least resistance, entering only through the upper hose instead, effectively killing any vacuum at the lower hose.

The only time you should NOT use an open lower outlet is in the case where the breather is routed to the air boot, as in the post DPW linked to. In that case, the breather is on the fresh air side of the filter, and having an open branch in the hose would result in a constant low velocity flow of unfiltered air into the intake tract due to the slight vacuum caused by the resistance of the air filter.

Running no lower branch means that there is no down/outward path for the liquid oil exhausted into the breather, and it would end up in the air box (or wherever).

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I was going to get some pictures of my set up, but with the bike at my parents house and me nursing a dislocated shoulder from the the weekend (twice in one race !), I dont have any pics yet as it hurts to drive any distance.

But, my oil breather is a 1" ID clear pipe coming straight up from the oil filler hole from a special plug, with the black head breather pipe T'd into it about halfway up with an special alloy T piece. The 1" ID clear pipe has a 2" dia K&N sytle filter on the end of it and sits behind the radiator and the filter is at the same height as the lower hole in the rad scoop.

Simple.

Now, I use my bike for SM only, and I am not sure if it will be OK for MX enduro use, but its been in some pretty sticky situations and not drawn in and water or dirt, the filter being behind the rad I havent seen it get mucky yet.

Being clear piping, you can see the oil mist condensing inside it which isnt much, and its a good way of checking rings/ cylinder as when my cylinder starting cracking, excessive oil residue was evident at the filter, then followed by oil in the water and water in the oil..big bores, makes me shudder now !

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I have ran my breather to my air box without the T and my motor smells like oil when I shut it down now? Is this the reason? 10 hrs on new wiseco. 05 450. What size hose do you use to run down to vents?

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It would always have smelt of oil the original way. It's simply a matter of the fact that you have moved the source of the odor that much closer to your nose, more than likely. There may also be some raw oil splattered out onto the inner surfaces of your air box that wasn't there before. I would use 12mm (1/2") tubing to run the down line. Also, it's best IMO to orient the T so that the straight through path runs from the head to the down line. This will enable the more complete exhaust of oil and crankcase vapors while not interfering with the operation of the line to the air box as the alternative path when the down line is submerged, or attempts to lift something.

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