Originally Posted by Ninja
Kawasaki Air Injection System
On most models takes the air for injection into the exhaust ports from the air cleaner housing.
The air injection system is controlled by a vacuum operated air control valve.
In most models it is controlled by vacuum, however in some new 2004 models this is now ECU controlled. See VN2000
The vacuum used to control the system is taken from the intake port of one cylinder. The vacuum pulls a sealed diaphragm against a spring to open the valve and let the air through the valve. The spring returns the valve to the closed position when the throttle is open.
As the vacuum system is sealed it does not change the mixture in the cylinder, which supplies the vacuum. It only opens under relative high vacuum i.e. throttle closed.
To prevent the chance of an exhaust backfire reaching the air box, one-way reed valves are installed in the cylinder head cover.
The system works by reducing unburnt hydrocarbons being emitted out the exhaust by injecting fresh air to completely burn any unburnt gasses under closed throttles.
It is not a new feature and has been used by Kawasaki for many years.
Kawasaki models vent the crankcase into the air cleaner housing to recycle any blow by from the crankcase back through the intake system.
Most models have only one crankcase vent. ZX636B 03 model last time I looked had only one crankcase vent, top crankcase at the rear.
The reed valves are connected to the exhaust port by a sealed tube. Sealed to prevent the oil contaminating the system of by having exhaust gases leak into the crankcases.
Possible performance issues with the KAIS.
Air leaks passed the diaphragm or leaking vacuum through an small hole in the vacuum line will upset the mixture in the cylinder operating the system.
Valve fails to open results in higher emissions.
Valve opens and fails to close the air injection is open and will circulate fresh air passed the reed valves into the exhaust.
CA models have additional tubes for the gas canister. Last time I looked 4 color-coded tubes connect to the canister. These control the flow of fuel tank gasoline vapour and any other gasoline vapour emissions back to the canister and recycle the condensed gasoline back to the intake side of the engine.
Down sides of this system, weight, many tubes and easy to connect wrong.
This not to say problems are not possible, in my experience it would be extremely rare considering the amount of Kawasaki sold with this exact same system.
All your fuctions of the Kleen system are 100 percent correct. But you are probably aware of Newtons law of pressure. The longer a distance air travels within a closed system, the less pressure and force it has as itís expanded. This is especially true with Kawasakiís kleen system.
The new 2004 Kleen system is a question mark as of right now to me. I donít know if it follows the same setup guidelines as the 2003 which was vacuum controlled, but Iíd be surprised it if was exactly the same. Especially after all the people whom were complaining about the system since it was first put on the bike in the first place.
By running the crankcase directly to the exhaust air value you are creating a tighter area were less air needs to travel in order to go the same distance. Not to mention there is always flex in tubing, etc because it is made of rubber.
Things which cause to much pressure loss include but are not limited to: Fuel return pump and the exhaust air switching value (The biggest force in horsepower loss using this system)
However the biggest factor in increasing the pressure and helping the accelerator is capping off the three vacuum ports/throttle bodied . This has the biggest impact on how fast your bikeís throttle response will be.
You donít have to take my word for it. But Iíve done this to not only my bike, but my brothers bike. And it has made a huge difference for both of us. Iíve also researched this topic so many times my eyes are starting to bleed. The most common response people say is ďI feel like the bike revís faster, or the throttle is quickerĒ. Hence the reason for doing this conversion in the first place. Some of the people who are far knowledgeable than I on www.kawiforums.com
have reported doing this system and having great results. Donít take my word for it, but you should check out there opinions and maybe take some of thereís.
Maybe this new system will be better since itís computer controlled now. If it isnít you can bet I the first thing I do is remove this crap.