Why does everyone ( OK maybe not everyone) remove or feel the need to remove the air suction valve and related hoses???

Total weight loss of the removal might be a pound at most of stuff.


It can not really hurt performance to have it in the system. All of its action are down stream of the combustion of the engine and on a four stroke what happens down stream of the exhaust valves does not make much difference. Yes the size of the pipe ( diamater & length) and the flow of the muffler can change performance but really how does the Air Suction Valve hurt the performance of the bike???

The valve adds air to the exhaust after the exhaust valves in order to help in a better burn of the exhaust gases and un-burnt fuel leaving the engine.

So how could or would this hurt performance of the engine??

Something to think about: Why do some wrap their exhaust pipes?? They think it looks cool? They do not want to burn themselves or others? The correct reason is because the exhaust gasses flow faster when they are hot and the wrap keeps the pipe hot. The faster flow helps produce better power.

Now adding clean air to the exhaust as it leaves the engine will help the un-bunt exhaust gasses burn which creates more heat and should cause the exhaust to flow quicker. Is not this the out come of the Air Suction System???

 

Because that's what we do?

 

Although it may cause slightly more pollution the exhaust won't get as hot. Also weight reduction.

 

Wrongo, otherwise everyone would be running their engines lean, which also creates hot exhaust temps. Hot exhaust temps in a turbo application are also not desirable. Why is that?

The problem with the smog crap is that it is NOT there for performance, its their for emissions. Without header wrap the excess heat is dispersed through the outside of the pipe, which does not help the exhaust gasses travel faster.

 

I left mine intact until the 351 mod as it comes with a cool block off plate, I saw no good reason to remove it but it had nothing to do with being green as I promptly changed the stock obstruction also known as the muffler and didn't feel it would make much difference either way if it was in place or not. On a side note is now it's removed my exhaust is still hot when the motor is running.

 

Running the bike lean is totally different in that it changing the performance of the engine and in turns produces heat in the wrong way. I am talking about what happens after the firing of the cylinder not trying to created more heat by producing a lean situation in the cylinder.

Yes from my understanding of turbo systems to much heat is bad because the exhaust vane and the intake vane of the turbo unit is connected by the same shaft and the heat can be transmitted from the exhaust side to the intake side and we know that heat is bad for the intake charge. One of the reasons that a turbo requires or should use an intercooler is that when you compress air it heats up in the first place and also the fresh air going through the turbo comes in contact with the turbo body which is connected to the exhaust side of the turbo. I am sure most of us have seen a video of a turbo motor running and the exhaust side of the turbo is cherry red. The intake side is just a few inches away from that cherry red glow. Yes, heat is bad in the intake charge or the combustion chamber it it is running lean but not that much of an issue in a non turbo exhaust other than burning someing.

The last time I looked I did not notice a turbo on my bike from the factory.

But does the emissions stuff of the KLX (Air Suction Valve) hurt the performance in any way? I do know that some of the smog stuff out there will hurt performance but the Air Suction Valve found on the KLX does not require any power other than a suction pulse from the carb to operate. Yes, its one pound of extra weight in theory could slow the bike down.

As for the header wrap it does hold heat in but so does the stock pipe over a thinner aftermarket pipe. If the (ASV) generates more heat than stock in the pipe it should also generate a greater exhaust speed which inturn should produce more power. Not much but in theory.

 

The point I was trying to make, is that if heat from running lean doesn't help exhaust gas escape faster (regardless of the power the engine makes), the smog system won't make a difference either regardless of hotter temperatures. Without header wrap (or preferably a high temp coating) the benefit of hotter exhaust gasses is nil.

 

ktm433, the only real reason to remove the system is to lower the temps of the exhaust system - especially the header pipe. Doing so will allow one to ride more comfortably in hot weather - even in shorts. If you don't have tropical or hotter summers, you may not understand.

 

You got ripped off too?

 

It is there because of the catalytic converter. Replace the exhaust and it is no longer working anyways, so it gets removed.