Kleen air system... what is it? It's a basic air injection system that draws air into the exhaust system to lean out the exhaust gases at certain throttle settings. It, in conjunction wit the 2 catalytic converters in the stock exhaust system, lowers emissions to acceptable EPA levels so Kawasaki can sell the bikes in the US.
Who should remove this system? With the stock exhaust in place, I have read that it may be a good idea to leave this system alone because if you did not lean out the exhaust with the cats in place you
could cause converter clogging problems. No real proof if this is true or not... do so at your own risk if you decide to remove it.
If, however, you have installed an aftermarket full system on your bike and have no catalytic converters to deal with, you may want to consider this mod. I have installed an Area P quiet core system and ever since I have installed it, I was getting popping and backfiring at very small throttle openings around town and on downhill decel throttle settings. When I plugged the hose that ran from the airbox to the cylinder head, which is what the Kleen system uses to inject air into the exhaust, the popping and backfiring disappeared. It made a difference for me, so I decided to pull all the plumbing from airbox to cylinder head and plug the holes left by the hose and associated equipment.
This DIY shows how to remove the hoses and plug the holes left by it's removal.
Hose I removed is the 3/4" looking hose directly beneath the backbone of the bike with the gold colored keeper.
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Remove the keeper and pry off the hose.
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The hose is being pried off a vacuum controlled valve that needs to be removed. Simply slip it's rubber isolators off the bracket it sits on. From the valve, there is a short length of 3/4" hose that runs to the top of the cylinder head. Remove the hose from the cylinder head.
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Remove the the valve and 3/4" hoses from the bike. There will be a vacuum hose that ran to the valve. Follow it back to a T and remove the hose from the T and cap the spigot on the T. I bought some 3/16" vacuum hose plugs that fit the T.
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To make some plugs, I used 1/2"ID fuel hose, some old oil drain plugs I had laying around and some tie wraps.
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You need to plug the hole at the top of the cylinder head and the hole at the airbox where the 3/4" hose came from.
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And that’s it. The result is a lot less clutter under the tank area and hopefully no more backfiring and popping.
If I missed anything, I'm sure I'm going to be hearing about it.
Some pictures of the plumbing that was removed.
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More extra pics: