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Discussion Starter · #1 ·
Hello everyone, it's me again, for asking (dumb) questions.

What is the usage of Crankcase breather , and what does it do.

I googled about it, but i still don't get it, and conflicts.

others say a crankcase breather is used to re-route gases produced

inside the engine to prevent engine from pressurize,

but in the manual, it said remove the plug after riding under rain.

I did the same thing, but not even one drop of liquid or air is out from

crankcase breather.

so , what does a crankcase breather really do?

waste air trapper? (No air after I unplug)

and, After riding under rain? (why?)

Thank you!

p.s. Sorry for my shitty grammar , english is not my mother tongue. please
forgive me >.<
 

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It does exactly what it sounds like lets the crank case breathe. If it didn't have one it would build crank case pressure and start blowing crank seals. I don't know what this plug is that you speak of because my crank case breather hose is right by the kickstand with no sort of plug in it
 

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Mine has black plug at the end. Think it's supposed to be unplugged at each service and them take a look for anything abnormal. I've done mine periodically and nothing has ever dribbled out of it or been discoloured.
 

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The plug is in the "puke tube" (so called because of the odor of what collects there). I normally remove that plug, even on the dirt bike.
 

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Discussion Starter · #6 ·
but i just unplugged that thing , no odor at all, and it's so clean, my millage is around 1050km, plz explain, thank you!
 

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If there's no smell and it's not clogged, you're fine.

Don't ride around without the plug in. If the crankcase develops negative pressure (vacuum) you can suck all kinds of crap up that tube, like water and sand, which are the last things you want to make their way into the crankcase. The plug is there to ensure nothing is drawn up into the tube if the pressure goes negative.
 

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Mostly water condensing out of the air in the crankcase, with whatever other crap (combustion byproducts) it picks up as it condenses and runs down into the breather tube.
 

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The byproducts are just gasses. You won't see them unless they get dissolved in something first (water) and you won't see any of that unless the temperature and humidity are just right.

You are the first person I've seen "complain" that their bike is running fine.. seriously.. ;)
 

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Yes, all the bikes (should have) come with the plug. If it's missing, replace it before you hoover something up into the crankcase.
 

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On certain older bikes, there was a positive correlation between the plug being left in and the crankcase seals failing. Old habits die hard.
 

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^ Eeeep...
 
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