Crankcase breather on a Honda VT750

on March 05, 2020

Are you wanting to upgrade the performance of your Honda VT750 bike, with new stacks, exhaust or tuning it? Make sure that you are properly taking care of your crancaske breather.


TJ in his latest video shows you what a crankcase breather is and what do about it on your VT750. So if you are in the process of adding some performance upgrades such as a Velocity Stack, exhaust, tune your bike you may encounter a bunch of hoses and BS underneath. One of those hoses leads to a little box, it looks like a early version of a british tank… in my opinion. That is where your crankcase breather is, it is very important for your bike because when you have pistons moving up and down in a motor its going to create pressure in two different directions. when it comes up it creates pressure above, when it moves down you’re creating pressure in the bottom of the motor, that pressure has to go somewhere.

If you don’t have a way for that pressure to vent then you will end up putting oil and air out of the weakest point in your bike. You got gaskets and seals all over this bike. they’re all over the place you even have them on your pistons. and if you don’t let this pressure out of the motor  it is going to find the weakest link and get out that way. and its not going to be fun- you will have oil spewing out everywhere. most of the time i see the oil coming out from below the cylinders that only happens if you plug your crankcase breather. If you plug that pressure can’t going anywhere. as you are all excited to add stacks and tuning your bike, to make it super fast, you want to make sure to not plug the breather. instead you are going to take a hose  and run it down the back to the ground. If it becomes plugged, you are going to experience some not fun stuff, you  can get oil in your cylinders, you’ll get oil out of your gaskets. As long as it remains open the pressure in the crankcase can then be equalized. So that being said, don’t put a filter on it, not a good idea!

The reason I would recommend that is because filter is actually going to trap any oil or moisture that comes out of here. that means the motor won’t breathe. think of water boarding your bike. there is no ability for the crankcase to allow air in as the pistons move or push air out. if your bike, is running and you put your finger over the hole, you will feel little pulses. You will feel air being pulled in and pushed out. it’s really gentle, but there will be some kind of mist over a period of time. Honda generally has a tank running to collect that and will collect at the bottom of the filter.

The EPA- government would not allow Honda to spew refuse all over the ground. they had to find a place to put it. Main take aways make sure it is not plugged, and it is vented! 


To learn more watch the video below! 

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