Removing Air Suction Valve System: WHY???
 

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? :confused:


:rolleyes:

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.

hook it up to the crank vent hose. Free crankcase evac system !!! massive powah !!!!

No, this basic design has been on Kawasakis at least since about 1979 before any introduction of a cat converter. I was working part time as a mechanic at a Kawasaki shop, and people would rejet their Kawasaki with this air injection system after installing an aftermarket pipe or muffler without disabling the system. The chromed pipes turned a dark blue for about 12" at the header pipe. Pretty ugly.:D

How many MPB* on that thing?


*Miles Per Bucket

Well It was just a guess.... You are suppose to believe every thing you read on the internet!

Explain how there is a difference between hot and hot? If your exhaust runs say 1700° with the air injection and runs 1700° with the wrap, what is the difference? If there is any gain with header wrap or ceramic coating to hold exhaust heat to maintain exhaust velocity it seems that the holding of exhaust heat through the air injector would do somewhat the same thing. But it seems no one has actually shown significant gain from either.

The only reason to remove pollution stuff that makes remote sense is the slight weight loss and the elimination of some stuff in the engine area under the fuel tank. There is no performance gain otherwise.

I was going to remove mine, but then when it came down to it, it was easier to just plug everything back in. As for weight - maybe I skip a few second helpings and save more. :o

I just read this... Another reason if you are running a chrome exhaust... but then it seems like a lot of those chrome headers turned blue due to lean jetting and the single wall exhaust tubing - the reason why the Japanese used to make them double wall. Of course now on the cruisers they use chrome covers up near the head to eliminate the problem by covering it up.

Not removing the air injection will discolor your expensive aftermarket stainless headers as well.

Lean jetting will do it too. Both run hot. Letting the bike sit and idle for long periods will cause bluing of chrome and discoloration of stainless too.

I will say ceramic coating doesn't discolor. May lose gloss, but stays in color.

My smog stuff is still on. It doesn't hurt anything and there is no performance to be gained by removing it. Heck, if the OEM muffler wasn't such a restriction and was louder, I wouldn't mind it being a cat converter either. I'm not a tree hugger but unless I get something for it, I don't see the benefit of making things pollute more.

Oh and I ride in shorts all the time. Ride hard even. That dang header pipe is hot so don't touch it. If you don't touch it then it's fine.

Puget Sound eh? Come on down to Dallas and ride in traffic with me @ 104 F ... Like I said - if you don't have tropical or better weather, you won't understand.

Whoopsie, haven't checked the thread haha...

Well the difference is that header wrap hold the heat in, which is what heats up the exhaust and helps it flow better. The air injection system heats the exhaust up and because the pipe is open to the outside air all of that heat is coming off the pipe, theoretically being *wasted* in the sense of scavenging the gasses, not to mention burning your legs.

I say get rid of it, it doesn't do anything good, it doesn't REALLY do anything bad, but removing it nets more gain than leaving it on. I waited until my big bore to rip it off, since I was already in there.

Actually feeding air reduces CO and unburned fuel... Pollutants. It doesn't cost any horsepower either. For that, I'm okay. My choice. If it was hanging off the side of the engine, like XR650Ls do, it would be gone. But where it's at, "it ain't eatin' any oats" so it's easier to just stick it back in there for now.

Fact is I got a few gaskets to see if I can make a block off plate that doesn't cost a fortune. I have to get a quote on cost. What would a fair price be? Remember postage would be maybe two bucks since it would likely weigh more than an ounce probably require shorter screws and gasket.

Well, i think the key is to not makethe block off plate as thck as bills, not sure why he does that, oerhaps to prevent warpage???? I say $15 is a good price, so ~$17 shipped?

I'm figuring 1/4" aluminum should do fine, maybe 1/8 stainless if reasonable.

Take off the pollution stuff then touch it and tell me what happens! :eek::D

I'm kind of betting it will burn the snot out of your fingers.

My 650 has no pollution equipment and I can tell you it gets hot too! Anyone actually taken any temp readings or is this guesstimation? Not that it really matters.

Yes Puget sound is where I live and yes we see triple digits. In the 90s just this week. I also ride in Eastern WA where it has been ridden in triple digits while I'm in shorts. Not as often as you Texans but perhaps you're legs are just softer? I do have pretty hairy legs along with moss on my back from all the rain.

You're talking about a 10-20 degree difference in ambient temps compared to a header pipe at what 1000? 1500? degrees. Meh.

Hey HB...that guy isn't a Texan, so don't besmirch our honor down here by claiming him as such...LOL!:D

It's an old issue in KF.. You don't have to take my word for it - If you research our threads, you'll find the info you need to make your own decision. I'd start by searching for "cherry".
I can save you the research as I've done it long ago.. The air injection system can cause an extra hot secondary burn in the header, especially after fattening up the AFR.

Here is a couple of excerpts from a little research...


Do you still have the fresh air injection system on the bike?...the one that allows air to pass into the exhaust after the combustion chamber to make a secondary burn for cleaner emissions. If the previous owner richened up the mixture to match an exhaust mod, with the stock system on there you could be getting a strong secondary burn in the exhaust with the extra fuel causing extreme exhaust pipe heat.

Otherwise extreme exhaust pipe temps are usually caused by an extremely lean condition, but with the stock system on there, that doesn't sound likely.
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Totally stock 2009 exhaust on my KLX gets ripping hot under normal driving. It stays hot too, long after the bike has cooled down that muffler is still scorching hot. With factory jetting if I run the bike with the choke on to warm it up for a couple of minutes the headpipe will glow red, visible in the dark only.

These new bikes are meant to use the exhaust system as an afterburner combustion chamber. Expect high heat. Not all cats need extra air to reburn the pollutants, I would say most modern vehicles use a cat that requires no air supply to work. Just high temps and pollutants.

In the OP's case, you are running rich with the stock exhaust. If there's enough air then it will be burning in the pipe.
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Sorry boys and girls, this thread must have been an unintended consequence of my wanting to remove the smog junk on my bike. Clearly I've started a proxy war via my last thread. I can't pick sides because I've got family up by Highbeam but I love Texas so I'll just sit back and enjoy my over priced Starbucks and moderate 70 degree weather here at home while I watch this unfold.

On a serious note I'll say I like clean air and water like everyone else. It's hard to be a gear head and for the environment when your dealing with internal combustion engines but we don't have to be Eco assholes either. I hate oil leaks, smoke, coolant leaks or just doing things counter productive to making power. I see validity on both sides of the argument.

My two cents

-Big Al

When I say making power I should have said with efficiency comes power. Not running rich or lean and so on, yes you'll always pollute more when you pump up a engine but you can still tune it properly and make it as efficient as possible for what your doing. I see guys, mainly in the automotive world, over fueling cars, running terrible intakes and just doing all kinds of crap that's useless.

In the street rod world they are getting both more power and clean burn. More and more in the aftermarket automotive area pollution is a concern for manufacturers due to E-checks. They have to make clean burning high performance parts if they want that big street scene sales.

Not so true yet on bikes though.

I don't know if I said it, but the main reason the pollution stuff is still on my bike is because I got lazy.

The cam work is done, valves shimmed, etc and everything is ready to button up... It was easier to stick the pollution stuff back on than to go about plugging this and that up. So I did, knowing it wasn't draining any power. I'm environmentally conscious due to laziness! :o

That's exactly it. The automotive worlds is leaps and bounds ahead of bikes, seems like it always has been too. How long until we started to see ABS brakes in more than just 2-3 models?

The 70s chevy pick up trucks in particular had a huge smog pump added to the belt assembly to reduce emissions. All these fancy ways for trying to reduce emissions caused for a motor that didn't run as well, and didn't pollute FAR less than without the device.

The key is as close to a full complete burn to optimize not only power, but also the lack of pollutants. Yes that comes with fuel injection and more computers to help the engine manage its burn, but if that's what it takes to make more power and less pollutants, that's what it takes. :D

RSM, I'm not sure I agree that the automotive world is leaps and bounds ahead of motorcycle technology. Of course we have to compare similar vehicles within each category and realize that there are some extreme differences in application for each. You can compare power output alone and other elements individually.

Your example of ABS between bikes and cars isn't really a technological argument. When ABS came out, most motorcyclists felt they didn't need or even downright "not want" ABS on their bikes. And when you consider an off road motorcycle probably should not have ABS...or at least not one that cannot be easily disabled...the argument of ABS as a technological feature may not be applicable between cars and bikes in many cases.

Many/most advancements in the car world are often geared toward safety, and many of them aren't that critical in a motorcycle comparison...or at least not necessarily wanted. If the market doesn't demand it...or the insurance companies...LOL!...it's not that such safety technologies can't be applied to a bike...it's that they're often not logical or demanded. And please...I'm not trying to throw safety issues out the window.

Lastly, if we're comparing performance parameters between bikes and cars, do some liter-to-horsepower comparisons in a realistic sense. I say "realistic" because comparing a Bugatti Veyron to even a ZX14 is a little silly. However, think about this. A Veyron is about 1000 horsepower with an 8.0L V-16...with 4 turbochargers. A ZX14 has about 200 horsepower with a 1.4L inline 4. A liter-to-horsepower comparison actually places the ZX ahead of the Veyron...and that's with a normally aspirated engine.

Again, I'll stress that exact comparisons between car technology and bike technology may not even be in the same plane on many issues. A fun discussion, but a blanket statement probably can't realistically be made.

His location marker says North Texas and he wanted me to ride with him in Dallas. Isn't that Texas as well?

As I've said, that head pipe is hot and will be hot whether the smog stuff is working or not. Don't be a baby about it and don't think you'll "fix" it by removing smog equipment.

I burn wood for 100% of my home's heat, a renewable energy source that is carbon neutral, I must be an environmentalist? No, just cheap and like to burn stuff. Sometimes we can accomplish things without even trying.

I understand that completely, but there is always a transition. Cars had ABS before bikes, cars had fuel injection before bikes. Air bags and seat belts are not YET applicable, but who knows what the future may bring. Cars now a days also have accident avoidance (lasers see the rear of a car coming up fast then assists in braking if the driver is distracted) which could be beneficial to a newbie rider who "freezes" on the bars. Of course with this would need many sensors to know weight of the combined vehicle to be stopped, traction conditions, tire pressures, lean angle etc. etc. as to not lock up the wheels. but i digress

I'm just talking in generalities of course. Gasoline car emissions are also vastly more advanced than motorcycle emissions. Diesel is just recently being forced to undergo emissions systems.

The market is vastly automobiles with gasoline engines, so most of the technology and effort in put into the items that are most used and highly sought after.

I think the Goldwing has an airbag...not sure about any others. Yes, cars have stricter emissions requirements as a rule, so motorcycles won't go there until they absolutely have to.

LOL!...HB, for some reason I thought we were refering to klx678, and I was giving him some jazz. klxster is definitely from TX. Sorry 'bout that.:D

Not all Wings have air bags. Motorcycles are starting now, with the cruiser aftermarket starting to make EPA/DOT approved replacement pipes now that the law is starting to clamp down. That was my actual point - the automotive market has tighter enforcement and thus the aftermarket has to make the stuff to suit, bikes don't... for the most part.

No idea about the pokage of fun at me... didn't read the stuff about riding in TX... to damn hot there!

Ever tightening emissions (pollutants and noise) regulations led to the major changes in automobiles. While we scoffed at the initial systems, current systems, FI, CPUs, etc, have led to 2 liter engines making 250+ HP while getting well over 25MPG. Bikes are headed down that same path.

Accurized®


;)

How would it sound at $17 including shipping and the gasket needed? 1/8" stainless steel with OEM gasket (about a $2.75 part).

I believe it may be doable.

:confused: Seems more than reasonable to me. You could start out as such, then when people request a gasket with the kit just bump the price up to ~$20-$25. Some people have a hard time locating gaskets. :D