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.

14034

Remove the keeper and pry off the hose.

14035 14036

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.

14037

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.

14038

To make some plugs, I used 1/2"ID fuel hose, some old oil drain plugs I had laying around and some tie wraps.

14039 14040

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.

14041 14042

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. :p

Some pictures of the plumbing that was removed.

14043 14044 14045

More extra pics:

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.



I know for a fact that an over rich condition will melt those honey comb cats and casue flow problems. It's really funny what Kawi is calling a cat on the 250r. That same piece in the muffler, is in the header. So from the Y-pipe juntion, to where it bends to go up to the muffler. Theres one of those so called cats. If you have the muffler off, look down in there with a flash lite. You will just see the end of it. I ran a bore scope thru there, it's open thru that piece to the y-pipe(just as it was in the muff).
I think next time we have the bike apart, we will plug off this AIS system also.

Heres a pic of that piece that came from the muffler. I dont see any real way to remove it from the header, but to cut at the y-pipe.... remove and weld back up. Dont think it would be worth the effort.

So anyway, plugging off this kleen air system (AIS) should be a good mod for those with slip-ons.

Yours looks way different than my pre-gen. How would I go about doing it on my bike?

And yes I did search, that is how I ended up here after wadding through 3 pages of nothing useful.

Yours looks way different than my pre-gen. How would I go about doing it on my bike?

And yes I did search, that is how I ended up here after wadding through 3 pages of nothing useful.

I don't have a service manual for the pre-gen, but from the looks of the parts diagrams on bikebandit.com there is no kleen air system on the pre-gens...

I don't have a pre-gen so I could be wrong.

http://www.bikebandit.com/houseofmotorcycles/kawasaki-motorcycle-ninja-250r-ex250f9-us-1995/o/m4025

I don't have a service manual for the pre-gen, but from the looks of the parts diagrams on bikebandit.com there is no kleen air system on the pre-gens...

I don't have a pre-gen so I could be wrong.

http://www.bikebandit.com/houseofmotorcycles/kawasaki-motorcycle-ninja-250r-ex250f9-us-1995/o/m4025

Wow nice link. The thing I want to remove is the fuel evaporative system (schematic shown in that link). Part # 16165 is loose and flops around. No way to re-secure it and its driving me crazy.

Wow nice link. The thing I want to remove is the fuel evaporative system (schematic shown in that link). Part # 16165 is loose and flops around. No way to re-secure it and its driving me crazy.

I would maybe consider just buying a new strap pn/92072 on those diagrams and keeping the system intact.

If you are interested in removing it, I would read through the following two pages. From what I can tell the red and blue color coding is similar between pre-gen and new-gen bikes.

http://www.ninjette.org/forums/showthread.php?t=22296&highlight=emissions
http://faq.ninja250.org/wiki/Hose_routing_for_California_emissions/3_line_fuel_tanks

hi Kelly,

need your advice/help.

i went through your DYI one last time after having removed the kleen air from my bike, and noticed a little difference between our bikes:

in your picture you have like a 4 way splitter i think?

http://img.photobucket.com/albums/v86/wayanlam/DSC04320-1.jpg

did you plug the one end that went to the kleen air valve with the blue bit?

where do the other two tubes go?

on my bike when we took it apart, i had a 3 way splitter, one from the fuel tank, one to the kleen air valve, and one to the carb.

since we took out the end from the kleen air, we were left with just the fuel tank and carb, so we connected that direct:

http://img.photobucket.com/albums/v86/wayanlam/28092009475res.jpg

i haven't had any problems with the bike since i did this mod, so i think its ok, but id still like to know if that's what i was supposed to do, to avoid any problems down the road because i was too lazy to ask :rolleyes:

thanks bro~
W.

on my 4 way splitter, one goes to the carb, which is the vacuum source, one is capped, one goes up to the fuel petcock (I think) and the last one is a separate hose I added which runs out to the side panel so I can check the carb sync easily.

you should at least have a hose that goes to the back of the fuel petcock off a 3 way splitter. do you?

yeah, well i have the hose going directly from the vacuum source (the carb) to the fuel tank (petcock) its the smaller hose plug, next to the fuel outlet. i wasn't, and still am not quite sure what it does, nor what the vacuum source does, lol

i removed the 3 way splitter since i didn't have anything to plug the 3rd tip with, and just went direct.

how can u check your carb sync, and whats the use to do so? i think i remember browsing through a thread that looked into that, but was a while back, and i read it before i even had the 250, so i didn't really pay attention to it.

thanks!

syncing insures the carbs are pulling equally by adjusting a mechanical device/linkage which controls the carb butterflies. I suggest you reread that post on syncing for a better explanation and understanding on how to do it.

A properly synced bike will run/idle smoother and pull harder from the low to midrange.

Hi All,

I have a 2009 CA model.

First, thanks for the insight of correcting the popping / back-firing symptoms.

My plumbing is close to as pictured.
http://lh4.ggpht.com/kkim993/SFWwGGzGJ3I/AAAAAAAAAW8/lGHk8aEaJNs/DSC04346-1.JPG?imgmax=576

However, my CA model / version has a "T" that splits the hose (long hose pictured above) between the Vacuum Switch (Item 7, p3-6 of owners manual) and the Air Box. The split line / hose connects to the Canaster (Item 2, p3-8 of the owners manual), located on the left side of the motorcycle.

Therefore, I capped / plugged off the "T" end that goes to the Vacuum Switch. The other two hoses I left connected (to Canaster & Air Box).

I did follow the other steps of capping / plugging off the Valve Cover (or cylinder head cover) spout and the small 1/8" dia vacuum hose.

Question for the experts, why cap / plug off the valve cover (cylinder head cover) spout?
Does it blow or suck air (to/from the Vacuum Switch)?

You can also grab on of these plate's here to make for a cleaner look:
http://www.shop.kyleusa.com/product.sc?productId=185&categoryId=121

This mod afect performance or just remove the popping and backfiring decelerating?

This mod afect performance or just remove the popping and backfiring decelerating?

definitely removes the backfiring/popping sounds, which in turn lets you drive the bike a lot harder (by not feeling like a fool backfiring throughout the whole ride, lol) so yeah, in that case i would consider this a performance mod :rolleyes:

Do you guys think there is any negative effect to the extra pressure in the top of the case from this being plugged up?

Well, FWIW it's negative pressure (suction) at the top of the cylinder head cover where short big hose of the the Kleen Air attaches. I've plugged it with my hand before, testing the sound of sealed vs unsealed. It's not a whole lot of pressure. Given the thickness of the metal used (even if our engine is mostly aluminum), I'm not concerned in the least.

Well, FWIW it's negative pressure (suction) at the top of the cylinder head cover where short big hose of the the Kleen Air attaches. I've plugged it with my hand before, testing the sound of sealed vs unsealed. It's not a whole lot of pressure. Given the thickness of the metal used (even if our engine is mostly aluminum), I'm not concerned in the least.

Its not a suction at idle, its blowing out a pretty good amount of air...

I'm more concerned about the gaskets, not the metal of the engine.

Anyone had experience on doing this Mod' on an FI bike?

The only thing I could add to this is that when I did mine, I went to the local auto parts store to get the "vacuum plug" for the T joint and right next to where they are located I found random elbow junctions, so rather than buying a cap I got the elbow and replaced the T junction. here is a pic of what I exchanged, on the right is the original, on the left is the replacement. It makes for a cleaner install.
http://i739.photobucket.com/albums/xx36/Kitdog0218/DSC01467.jpg

Thanks KKim - based on you DIY I managed to remove the Kleen-Air system from my FI bike. The back-fire was greatly reduced - I haven't had any since! There were a few different things from your carburetted bikes so I guessed a bit - after taking the tank off /re-installing it 4 times to check/correct my mistakes - everything is done! The bike is running great. Thanks again.

For removal on FI 250R.

There is no 3rd hose, only the 2 large ones are there. There is an electric switch which operaters the valve here, instead of vacuum. Thats why there is no 3rd hose, but the switch, needs to stay on the bike for the FI-light not to light up. I wrapped the 2 ends in some electro-tape and placed it back on the bike. No air going through it, so the valve isnt doing much, but it keeps the warning light off. ;)

Thank you, Simen, for your contribution. Good stuff! :thumbup:

Just to add to Guinss's post - our FI bikes here in Thailand has another hose which goes to a "cannister" - same as So Cal bikes.

Sling Shot Racing has this nice cap for the 250.

http://farm5.static.flickr.com/4075/4778111993_3e4ae3f2c6_m.jpg

Hey I was doing this to my CA model 250r.. and I have a question about some extra hoses.

Do I take these hoses off too and plug off that port? (the bundle that I'm holding)

http://i924.photobucket.com/albums/ad83/mechdrew40/2010-08-052010-08-05002015.jpg
http://i924.photobucket.com/albums/ad83/mechdrew40/2010-08-052010-08-05002019.jpg

if it's no longer connected to anything, yes. :)

Oh ok great, so I guess for the CA models you need to plug up 3 holes? 1 on the air box, 1 on the carb, 1 on the crankcase

Crankcase? :confused: Sorry, not familiar w/ CA stuff, but a pic of the crank vent would help.

Crank vent, I'm sorry. The silver square on top! With the silver tube coming up like a chimney

Crank vent, I'm sorry. The silver square on top! With the silver tube coming up like a chimney

picture please. there is a crankcase vent that you do not want to block. I want to make sure exactly what we're talking about.

*gets off lazy butt*

Here is the hole on the top of the engine

8612

Here is the hole on the carburetor (brass fitting)

8613

Thanks for all your help :)

Well, you do need to cap/plug the airbox hole and "chimney" at the top of the cylinder head.

That brass fitting on the carb is a vacuum source. What was connected to it before? I seem to remember more than one thing was connected to each of the vacuum ports on the carbs. (brass fittings)

Oops. It was connected with a T, and I don't quite remember where they hooked to to before. I'm going to have to try to pull up the diagrams for this

kenny I'm in the same boat.....got everything plugged but not sure what to do with the brass fitting on the carb....hhmmm....

With some help from another member here, I learned that it's goes from the carb, to the bottom of the gas tank. It goes into the petcock. I just blocked off one side of the T and then put it back into the tank.

aaahhhh i see....thanks for the help!!!!

DIY on removing kleen system made it a chinch...not sure if i like result but ill give it a ride or two plus with me about to shim and desnorkle i may be surprised.

DIY on removing kleen system made it a chinch...not sure if i like result but ill give it a ride or two plus with me about to shim and desnorkle i may be surprised.

was your bike backfiring/popping after you put the exhaust on it?

All the time especially when i first started up...it kind of seems like its starving for air now...i didnt run it for long but i'll crank it up when i get homme and get back to you.


Sorry i put in wrong section Alex,dont mean to make you work!!:D
Side note: I should get that green and white smiley face on my bike...

All the time especially when i first started up...it kind of seems like its starving for air now...i didnt run it for long but i'll crank it up when i get homme and get back to you.




starving for air means you think the bike is running richer, not leaner. I think with the mods you've done and not doing anything to the jetting (I don't see anything mentioned in your sig) has you ruining lean, not richer. watch out you don't do damage to your engine if you haven't adjusted your jetting to compensate.

I don't think you'll want the smiley face if that should happen. :(

Kind of a dumb question... do you need to rejet after doing this mod?

no

Am I going to have to do this if I just get a slip on?

if it pops on decel after you install it, yes. :D

the most accurate answer is... most likely.

Awww crap. That looks complicated:(

it's not, really. if you get stuck, post up your problem and I'm sure someone will be able to help you sort it out.

btw, you don't have to do this mod if you add a slip on. you can just live w/ the popping... some people even like it that way.

What if I have popping on decel with my stock exhaust? Haven't touched the carbs or snorkle. My exhaust valves are apparently too tight though...

What if I have popping on decel with my stock exhaust? Haven't touched the carbs or snorkle. My exhaust valves are apparently too tight though...

how do you know that? :confused:

how do you know that? :confused:

Doing my 12,000 km valve adjustment today. I need to take better measurements (my feeler gauges suck, the values jump from 0.15mm to 0.18mm to 0.20mm), but they're definitely between 0.20mm and 0.23mm.

Great write up Kim! But I'm wondering if I'm wrong here.

I thought the kleen air system was designed to vent valve-train pressures and vaporized oil to the airbox and thus get burned through the engine, instead of venting to the atmosphere. I thought the extra oil in the air/fuel mixture is what caused the popping in the exhaust?


I didn't realize it injected air into the exhaust system? I thought the valve train was sealed from the combustion chamber? Isn't that what the valve seats are designed to do? And I haven't seen a port leading to the "chimney" on the valve cover from the exhaust ports. What am I getting wrong here?

I removed mine a while ago, simply because it makes maintenance easier. I then put one of those little K&N breather filters on there, and I think it makes it sound awesome. Valve train noise is a little louder, and it makes the thing sound like a machine.

I thought the kleen air system was designed to vent valve-train pressures and vaporized oil to the airbox and thus get burned through the engine, instead of venting to the atmosphere. I thought the extra oil in the air/fuel mixture is what caused the popping in the exhaust?


I didn't realize it injected air into the exhaust system? I thought the valve train was sealed from the combustion chamber? Isn't that what the valve seats are designed to do? And I haven't seen a port leading to the "chimney" on the valve cover from the exhaust ports. What am I getting wrong here?



from Sport Rider magazine...

KLEEN(tm) (Kawasaki Low Exhaust Emission) System

* Helps keep exhaust emissions environmentally friendly
* KCA (Kawasaki Clean Air) system routes fresh air to the exhaust ports for reduced exhaust emissions

http://www.sportrider.com/bikes/2004/146_04_kawasaki_zx_6rr_features/index.html

If I just clamp the big tube leading to the air box will it have the same effect? I want to just test the effects out w/o removing everything for now. I have way to much popping on throttle let off with my slip on. Used to sound cool now it just gets annoying as it causes way to much attention. (thats bad?! :rolleyes:)

If I just clamp the big tube leading to the air box will it have the same effect?

i believe it might have the same effect, i saw a bike at the mechanics that did that. the mechanic told me that the owner was too conservative to take it all out, and opted to just plug the big pipe that used to plug into the air filter.

try it out and when you find that it has eliminated the backfire, buy this cap and close it off for good :p

http://img.photobucket.com/albums/v86/wayanlam/P1070088_resize.jpg

nice and tidy under the fuel tank now. and a little lighter :rolleyes:

Looks good Wayan. Alternatively, you can DIY a blockoff cap for almost free using some spare thick-ish sheet metal (think it was 16 gauge) and using the OEM breather valve (what the blockoff plate replaces) as a pattern.

yeah, i researched it a little over here after i got this bit. and i found that i could get a sheet thats 200 x 100 x 0.6 cm of billet aluminium and get almost 500 of these from that one sheet, making the material cost roughly 50 cents, lol

labor cost to cut them out (manualy at a metal lathe place, not CNC) would cost another 2.5 buks. so theoretically i could make them for $3. but thats just too much work and too many pieces, haha... unless someone wants to buy the other 490~ bits!

I'm sure you could probably sell at least half of 'em to forum members. I know my little dremel-cut blockoff plate took a lot longer to get looking decent than I wanted it to; time I could've spent doing other things like riding.

I just removed the kleen air system and I just plugged both ends. I purchased the block off plate, but when i removed the oem plate, i noticed it had a gasket while the new plate did not. Just wanted to double check that is how it's supposed to be. I assume it's fine, but nothing wrong with double checking :)

if the oem plate uses a gasket, I would advise to use a gasket with the new plate... or at least some sort of gasket sealer type of material. last thing you would want is an air leak there.

hey justin, the gasket (rubber block with a metal spring valve) sometimes sticks to the OEM plate. all you need to do is pull it off, and put it back in the hole (the right way round).

in my case the rubber gasket stayed in the bike, i took it out, and cleaned it up before putting it back in and closing it up with the new block off plate.

hey justin, the gasket (rubber block with a metal spring valve) sometimes sticks to the OEM plate. all you need to do is pull it off, and put it back in the hole (the right way round).

in my case the rubber gasket stayed in the bike, i took it out, and cleaned it up before putting it back in and closing it up with the new block off plate.

Makes sense, thanks!

Same deal for me; it stayed in there when I pulled my breather valve off, but I pulled it cleaned & replaced it. Also put a little high-temp gasket sealer around the outside metal rim, just to be sure.

Am I going to have to do this if I just get a slip on?

My question as well? :confused:

if it pops on decel after you install it, yes. :D

the most accurate answer is... most likely.

And answered.. :thumbup: :D

Sorry to revive this DIY but I gots a question for y'all. I've got PODs and the Kleen air system removed from my bike (shop installed when I took in for an initial checkup/rundown). Finally decided to take a peek at this today and I've got a question. Instead of blocking off the hole in the cylinder head I've got a tube that runs back to another hole under the carb assembly ontop of the case (possibly the crank case vent-port right next to the VIN?). Is this a horrible idea? Should I remedy this ASAP? Am i going to blow myself up? Should I stop drinking so much? Thanks in advance!

Edit: Just went and looked...this is definitely whats going on.

Ninja Edit 2: stolen from another forum...sounds like its not a big deal:

"By tying the two hoses together air can't go anywhere. Hence the valves don't open (and air doesn't flow into the exhaust). Block off plates accomplish the exact same thing and like you said, it looks cleaner.

What you're talking about with the crankcase vent is referred to as "Crankcase evacuation".

Normally you don't want crankcase pressure building so any positive crankcase pressure is pulled into the intake tract and burninated. The mod in question ties the crankcase vent to the clean air system. So the reed valves STILL function, but instead of pulling in fresh air (and causing popping on decel) you're pulling in that ****** crankcase air (which doesn't go "pop"). This vacuum causes negative pressure in the crankcase which in turn causes the rings to expand (creating a better seal). So in turn you have a little more cylinder pressure and you make a bit more power.

It's probably hardly noticeable in this application, but if anything it's "free" horsepower, so why not. The only drawback with crankcase evacuation is faster cylinder wall and ring wear (not very extreme in this application), and in certain car engine applications can starve the valvetrain of oil."



...maybe i'll leave it

Sorry to revive this DIY but I gots a question for y'all. I've got PODs and the Kleen air system removed from my bike (shop installed when I took in for an initial checkup/rundown). Finally decided to take a peek at this today and I've got a question. Instead of blocking off the hole in the cylinder head I've got a tube that runs back to another hole under the carb assembly ontop of the case (possibly the crank case vent-port right next to the VIN?). Is this a horrible idea? Should I remedy this ASAP? Am i going to blow myself up? Should I stop drinking so much? Thanks in advance!

Edit: Just went and looked...this is definitely whats going on.

Ninja Edit 2: stolen from another forum...sounds like its not a big deal:

"By tying the two hoses together air can't go anywhere. Hence the valves don't open (and air doesn't flow into the exhaust). Block off plates accomplish the exact same thing and like you said, it looks cleaner.

What you're talking about with the crankcase vent is referred to as "Crankcase evacuation".

Normally you don't want crankcase pressure building so any positive crankcase pressure is pulled into the intake tract and burninated. The mod in question ties the crankcase vent to the clean air system. So the reed valves STILL function, but instead of pulling in fresh air (and causing popping on decel) you're pulling in that ****** crankcase air (which doesn't go "pop"). This vacuum causes negative pressure in the crankcase which in turn causes the rings to expand (creating a better seal). So in turn you have a little more cylinder pressure and you make a bit more power.

It's probably hardly noticeable in this application, but if anything it's "free" horsepower, so why not. The only drawback with crankcase evacuation is faster cylinder wall and ring wear (not very extreme in this application), and in certain car engine applications can starve the valvetrain of oil."



...maybe i'll leave it

why would you want to? :confused:

Because "Crankcase Evacuation" sounds awesome??

Seriously though, I'll probably end up going with a block off plate/breather on the crankcase vent but its good to know that its not the most uncommon thing in the world.

Update: decided to slap on a block off plate and run a regular crankcase breather. Bike looks cleaner, seems to warm up faster and have a bit more throttle response. Not sure if its in my head but glad I did it.

Total time:
Installing block off plate and breather- 7 mins
Shake down run around the block- 5 mins
Running out of gas on way back home, going to get gas- 35 mins
Having the gas tube pop off of the canister and go directly into my gas tank- 2 secs
Getting the damn thing out- 1 hr...


Im awesome!

I have a hose that Im not sure where it goes...it's coming up right out of the middle of the carburetor? Does that come off?

So, I have Kleen Air System off however, I have an extra tube. It was coming up right between the carbs...can that be remove?

Where does it run to? Sounds like the vacuum line for the petcock.

Does the other end of that tube plug into this?

http://lh4.ggpht.com/kkim993/SFTENCQHbsI/AAAAAAAAAUY/7OpNl0VwAoo/DSC04323-1.JPG?imgmax=576

Or is it a Skinner, thinner tube? If so, jojah's probably right. When you put your tank back on, you plug that tube back into the peacock that's under the gas tank.

Here are the hoses the extra one I am confused about is the bottom one
http://i24.photobucket.com/albums/c34/lillard28/hoses.jpg

And here is where it was connected...
http://i24.photobucket.com/albums/c34/lillard28/carbs.jpg

Take a look at kkims picture in my previous post. Do you have that long tube that is running down the middle and goes down the back? I'm pretty sure that's where it goes. One end connects to the carbs and the other end remains open. I think its for overflow. Can someone please confirm?

Yeah it wasn't connected to anything at all on the other end...so it just hangs there for air flow?

Its not for air flow... I'm pretty sure its for excess fluid/gas in the carbs. So they don't get flooded. Any excess just drips down to the bottom. There should be some mounted loopholes that you slide that tube through. It helps hold them in place. My bike has two tubes that just hang through there. But I think cause mine is a Cali model.

I figured it out and the bike it back together and running! Woohoo!

Have you rode your bike yet? Did it take away your popping with the two bros exhaust?

Nope, started raining here...
Posted via Mobile Device

I was looking at another DIY for removing the kleen air system and saw this comment. I'm wondering what you guys think about it? The poster seems to think the popping sound means we need better carb tuning.

The Clean Air System operates by using the carburetor intake manifold vacuum through the vacuum switch valve to create negative pressure in the crankcase. It then carries the crankcase / cylinder vapors to the combustion chamber to be burned. The vacuum switch valve of the clean air system also serves to function as a pressure relief point for crankcase / cylinder head vapors, in the event of an internal engine malfunction (much like the PCV system on a car). If this occurs, excess vapors are vented through vacuum switch valve into the air cleaner. One symptom of crankcase vapors flowing into the vacuum switch valve is oil residue in the air filter housing.

When the engine is running, a certain amount of combustion gas escapes past the rings into the crankcase; this is normal. When the engine is at idle, vacuum overcomes the spring tension of the check valve and causes it to move inward and restrict vapor flow into the intake. When the bike is cruising and vacuum is lower, the spring tension moves the check valve away from the seat, allowing higher flow of crankcase vapors into the intake. Control of crankcase vapor flow is used to prevent excessive amounts of vapors into the intake at idle speed. This could cause rough idle or incorrect idle speeds.
The air suction valve is on top of the valve cover and is attached by hose to the vacuum switch valve. The position of the air suction valve allows it to pull vapors from inside the engine without sucking oil from the crankcase (reeds on the underside of the air suction valve deflect and help separate droplets of oil from the blow by vapors). A hose connects the vacuum switch valve to a vacuum port on the air cleaner housing. This allows the vapors to be siphoned directly into the engine without gumming up the throttle body or carburetor.

Because the clean air system pulls air and blow by gases into the intake manifold, it has the same effect on the air/fuel mixture as a vacuum leak. This is compensated for by the calibration of the carburetor or fuel injection system. Consequently, the clean air system has no net effect on fuel economy, emissions or engine performance -- provided everything is working correctly. Combustion gases consist mostly of carbon dioxide and water vapor, but do contain small amounts of unburned fuel and other contaminants. Water and fuel vapors in the crankcase can react to rapidly break down and shorten the life of engine oil. In addition, these vapors contribute to the formation of sludge in the crankcase. The worst case scenario if the Clean Air System is plugged or blocked is blown seals, blue exhaust smoke, power loss, poor drivability, excessive carbon build up in the combustion chamber & possible head damage.

WARNING: Removing or disconnecting the clean air system in an attempt to improve engine performance, gains nothingand is illegal. EPA rules prohibit tampering with any emission control device. Disabling or disconnecting the clean air system can also allow moisture to accumulate in the crankcase, which will reduce oil life and promote the formation of engine-damaging sludge.

Backfire, popping, knocking, crackles...etc. is caused by a too rich or too lean carb. The amount of crankcase vapor on the carb and combustion system is nill, because of the calibration of the carb and the vacuum switch valve. Hope this has helped somebody.

Yikes, hope we don't ruin our bikes by taking off the kleen air system
Posted via Mobile Device

I just removed the kleen air system, air box, rejetted carb, installed k&n pod filter & then capped the hole left on the cylinder head as shown in this thread. Bike was running great, until the cylinder head gasket blew out. I can only assume this happen due to pressure build up after placing the cap where the kleen air system once was. I have replaced the gasket, & am now trying to figure out what should be done next. I did try placing a breather on the cylinder head, but now get fluxuating idle & popping like a vacuum leak. After placing the cap back on, it's back to normal. I don't want to leave the cap on, & risk blowing another gasket. Any suggestions????????

put the Kleen system back on?

Yours is the first I've heard having problems due to removing the Kleen system (if in fact your blown head gasket was caused by it's removal).

is your exhaust system stock?

Nope.... I have an LOR Slip on pipe....
Putting the Kleen Air System back on completely isn't a very attractive option, as the stock air box sucks! I may look at trying to use the vacuum switch that came off to act like a one way vent, to let pressure out, but not let air in..

you could put the Kleen system back on and put a filter on the end of the hose that normally leads to the airbox.

you do know that the reed valve type assembly that they are using as the Kleen system valve at the head only permits air flow in one direction, correct? I don't see how blocking that off could have increased your head pressure. From what I've read about the system, it simply injects/allows fresh air into the exhaust stream during throttle off conditions to lean out the exhaust gases to pass emission levels.

did you by chance remove that reed valve assembly under that cap/plate?

also, did your cylinder head gasket blow or your valve cover gasket?

Not really sure how the whole thing works....It was the valve cover gasket that blew out, it was a minor tear in the corner. If the Kleen Air System only pushes air in, & dosn't regulate any kind of pressure, then the cap should be fine. The bike was fine on shorter rides through town for a few days. The problem happend towards the end of a 20-25 mile ride....

Forgot to add that I didn't remove anything from under the plate...

has the valve cover ever been off?

Nope....Bought it new, and now has 1,500 miles on it....

dunno what to tell you. it does sound suspicious that you should blow a valve cover gasket after doing the Kleen removal, but like I said, yours is the first that I've heard about doing this. To give you a bit more confidence, they have been doing this mod on other Kawasaki models long before the 250 new gens ever came out and I've not heard of problems with those bikes, either.

I would keep it as is and see if you have further problems. If you do, put the Kleen system back in and install a filter on the end of the hose that normally would have connected to the airbox.

I would not do, as you suggested, to use the the valve to purge out gases from the head. Not only would you upset the exhaust system in it's entirety, but you would be purging hot exhaust gases into rubber hoses not designed to handle that heat load.... and, I might add, your gas tank sits right above that valve port. Please don't do this.

Hi Guys,

Although my problem isn't anywhere near as bad as the one above, I'm hoping someone here can help me out with the less than stellar results I'm getting with the kleen air system removed.

I took an evening last week to pull everything apart and remove the kleen air system exactly as described at the beginning of this thread. I removed the T connector (no longer needed) and ran a tube directly from the petcock to the carbs. Everything went really well, and I even bought this kit to block off the port where the old system used to connect:

http://www.drivenracing.com/content.cfm/go/storeproduct/id/939/name/kawasakiblockoffplates

I bought my bike used and it already had a full yoshi exhaust with the stock air box and snorkel and a K&N replacement filter. It had been re-jetted for that setup, and was running very well with no backfiring.

After removing the kleen air system, my idle is now lower an wanders between 1000 and 1500 (used to be 1600 and very steady). Today my bike fully stalled while sitting at a red light with the bike in neutral. I also noticed that if I'm on the highway and let off the throttle, the bike seems to gargle a bit, and makes no power. If I open the throttle much wider, then it finally snaps out of it and returns to normal.

Is this to be expected? Should the change be serious enough to require re-jetting or otherwise drastically change the bike's performance? I thought that if the bike was running well with an aftermarket exhaust, that removing the system would be harmless?

Can anyone shed some light on what happened here? I know I can just put it back on, but now I'm worried that the issue is pointing to something else being wrong. Should I go all out and replace the filter box with a pod filter and have the bike re-jetted with that setup?

Any help would really be appreciated. I'm definitely a novice when it comes to engines, so hopefully someone here can shed some light on this for me!

Cheers,
Owen

sounds like you perhaps missed capping off one of the vacuum ports when you removed the Kleen system switch? there should have been a skinny hose that ran up to that switch. what did you do with it?

http://lh4.ggpht.com/kkim993/SFWwGGzGJ3I/AAAAAAAAAW8/lGHk8aEaJNs/DSC04346-1.JPG?imgmax=576

That skinny hose ran to a T connector that also connected to the carb and the fuel petcock. I removed the T connector and reused a section of hose to connect the carb directly to the fuel petcock, hence eliminating the T connector.

Does that make sense, or did I miss something? Where did that port on the top of the Kleen air valve used to lead to. Now that I look at it, I don't remember anything being hooked up there.

sounds like you got it correct. there was no hose connected to the top of that Kleen switch.

removing the Kleen system should have resulted with no changes to your fine running bike... obviously, something is not connected right. Check again to see if the vacuum hoses are properly connected and are not leaking or damaged.

when you installed the block off plate, you left the Kleen reed valve assembly inside the head, correct?

Hi kkim,

That's correct. I only disconnected the two bolts holding the old plate, and installed the new plate using the same bolts. I didn't remove anything below the plate.

I'll pull things back apart tomorrow morning and make sure none of the hoses have worked themselves loose. I was pretty meticulous, and everything was carefully reconnected, but who knows, maybe I missed something or kinked a tube.

Thanks for your help!

Cheers,
Owen

please update with what you find. I always thought this was a straight forward mod, but with what has been popping up lately, perhaps there is more to learn about this, collectively.

btw, yours is the first full system/slipon install that I've heard that didn't encounter the decel popping. do you happen to know what your jetting specs are?

I certainly will. I'll take everything apart and report back tomorrow.

As for jetting specs, I really have no idea since I didn't do the work. If I ever pull the carbs apart, is there any way to determine what it was set to? If so, I might be able to make a note of it if I ever get up the courage to rummage around in there.

Just to make sure I understand the kleen air system correctly, is the following true?

1. The actual vacuum pressure is generated in the carb.
2. The vacuum pressure opens the fuel valve allowing fuel to flow.
3. The same vacuum pressure also used to open the kleen air valve.
4. The kleen air valve used to allow filtered air from the air box to flow forward into the port on the top of the engine (presumably into the exhaust from there?)

I don't really understand how you would flow air from a low pressure zone (like the air box) to a high pressure zone (like the exhaust outlet) by simply opening a valve. If you did that, wouldn't exhaust air flow back into the airbox, not the other way around?

I just want to make sure I actually understand what this system does.

Regards,
Owen

that's the basic idea. the exhaust is prevented from flowing backwards towards the airbox by that valve I mentioned inside the head. It's a reed valve type setup that only allows flow in one direction.

so, the fresh air is pulled by venturi action (I'm guessing) through the Kleen air switch when the vacuum operated switch allows it, during off throttle applications.

as far as the jets, the values/sizes are stamped on the brass bodies of the main and pilot jets. The needles have grooves for clips that determine needle height. you would need to read the numbers off the jets and see what position the clips are on the needles.

The more research I do, I wonder if I simply had a faulty gasket from the factory, or the bolts may have become a bit loose after the 1,500 miles & needed to be retorqued. As they make block off plates and such for this, capping off the port should not be an issue. I may just need to ride it, and see if it happens again.....

Megan,

Please let us know how it turns out. The more info we have, the better we can come up with solutions should this mod cause problems we are not aware of. Like I said, yours was the first to date, but that doesn't mean it's not a problem. It does sound like the gasket was faulty, but if it happens again, we will know for sure something else is up.

Hi Guys,

Well I tore the whole thing back apart and double checked everything, and I'm positive it was all done correctly. None of the hoses were loose or kinked, and everything was connected as it should have been.

The first thing I tried was turning the fuel petcock to the "prime" position to see if it was a problem with the vacuum not opening the fuel valve. That made no difference, and the idle was still jumping around and dipping below 1000RPM, so I just set it back to "on".

I then pulled off the new block-off plate and took out the reed valves to take a better look at how they worked. I noticed they looked rather sooty, so I snapped a few pictures and cleaned them off carefully. They definitely only allow pressure in one direction (sucking air in, not blowing it out). Putting a block off plate on there certainly won't cause any undue pressure under there, otherwise the thin reed valves would have blown themselves out long ago.

Is that level of soot buildup normal, or is it trying to tell me something about how the bike is running? Too rich? Too lean?

I think I'm going to try putting the Kleen air system back on to see if things go back to the way they were before. If they don't, then it might be indicative of some other issue that just happened to pop up at the same time.

I'll keep you all posted.

Cheers,
Owen

Owen,

can't say what the valve should look like as I've never removed mine.

pull the spark plugs and see what they look like. that would give you an indication of how the engine is running and possible jetting richness.

Well, yet another update. For whatever reason, my bike runs significantly better with that top plate allowed to vent. I pulled the block-off plate off, and put the stock chimney back on. I then ran the longer hose off the chimney which let me block and unblock the chimney with my finger while the bike idled and with some throttle.

With the chimney blocked off, the bike idles between 1400 and 1100, and when I blip the throttle, it revs up and then drops to around 1000, almost stalling, before slowly climbing back up.

With the chimney open to free air, the bike idles steadily at 1600, and when I blip the throttle it doesn't dip any lower than 1500, and therefore doesn't stall.

It's like a night and day difference.

So now what? Do I put the entire system back on, or do I just go buy a small in-line filter and put that where the Kleen air system used to be?

Cheers,
Owen

my guess is that the bike has been jetted richer in the idle circuit to compensate for the Kleen system in operation. when you removed the air source with the block off plate, the bike runs richer, which would account for the lower idling.

like I said, pull the plugs to get an idea if your bike is running rich (plugs will be black).

otherwise, I would put the Kleen system back on and live with it. It seems your bike ran well with it on. :)

I would not simply put a filter on the hose leading directly from the "chimney" as that would supply extra air all the time to the exhaust flow, which might lead to a too lean condition at other throttle positions other than at idle, which that switch controls.

I went for a quick ride with a cloth tied around the open end of the chimney, and for the first time ever, I was getting the backfiring everyone is talking about! When I let off the throttle, I would get several loud pops, and occasionally when shifting gears. With the kleen air system on there and the full yoshi exhaust, I never once had it backfire like that. Do people really ride around town with it sounding like that? It was horrible!

Anyhow, the whole thing is back on, and it looks like it's there to stay. For whatever reason, someone must have worked hard to dial it in with that system in place, so I'm going to leave it alone. The bike runs noticeably better, and there is without a doubt more power in the lower rev range with it in place. now I just have to put my poor bike back together for the fourth time!

Cheers,
Owen

just curious, did you use your choke when starting your bike prior to this?

I've only used it a handful of times when it was below the freezing point here. Otherwise, I never need to use it.

Does all this point towards the bike running a little rich? If it is, should I try and pull the snorkel to see if that helps?

Cheers,
Owen

to me, that says it's a bit rich in the idle circuit.

as for pulling the snorkel, I'm hesitant to make any recommendations with your bike based on my track record so far. :lol:

seriously, w/o knowing the jetting, it's very difficult to make recommendations. the main jet mainly affects high rpms... how does it pull from 9k to redline?

Happy to report after changing the gasket, & a test ride, bike is good to go! As always, thanks for your quick feedback, knowledge, & ideas!
Next on the list of mods:
Tire upgrade
Relocate Rear Brake reservoir (Under seat where air box used to be)

My idle dropped down to 1k after kleen mod and bike requires choke to start. Ran fine prior and only other mods are snorkel and 2 shims. According to the previous replies, it sounds like I'm running rich. Everything is connected or capped correctly. I can only assume that my bike was originally set-up optimally at the factory and I may have already been running rich with the 2 shims prior and some how compounded the situation by restricting air that was going into the crankcase. Is this possible?

I did not have any issues before shimming. Just assumed it didn't hurt since I did the snorkel and 250s are notorious for being lean. Haven't had time to tear her down again but prefer not to re-install kleen so suggestions would be appreciated.

Where does your bike idle at now, when fully warmed?

I adjusted back to 1.5k last time and low-end seems weak and ilde a bit lumpy. When I started it again this morning it was back at 1k. Didn't have time to warm it up again. Just gave it shot before leaving the house.

Hi dragonboy,

Sounds like you're having a similar problem to what I had. I just spent the weekend pulling out my air box, kleen air system, and installing a K&N R-0990 and Factory Pro jet kit.

My new setup is running really well, and finally lets me get rid of the kleen air system without any issues. If you really want to get rid of it, I would suggest dropping the $30 on the K&N filter and the $80 on the Factory Pro jet kit.

Before installing the above, I actually fully re-installed my Kleen Air system because the bike ran significantly worse without it. I'll post up the jetting that my bike had prior to the airbox removal in the jetting database, which might shed some light on your problem. I think for some specific jetting and bike setups, you're better off not removing the Kleen Air system.

Cheers,
Owen

Thanks opc! I'm going to try removing a washer to see if it helps. Don't really want to mess with a jet kit and recently installed a Uni filter. I'll report back.

Wonder if anyone else had a similar issue. Also, did you confirm that you were running too rich when dialing in your jet kit?

Guess worse case I reinstall the kleen system. :-(

Hi dragonboy,

Sounds like you're having a similar problem to what I had. I just spent the weekend pulling out my air box, kleen air system, and installing a K&N R-0990 and Factory Pro jet kit.

My new setup is running really well, and finally lets me get rid of the kleen air system without any issues. If you really want to get rid of it, I would suggest dropping the $30 on the K&N filter and the $80 on the Factory Pro jet kit.

Before installing the above, I actually fully re-installed my Kleen Air system because the bike ran significantly worse without it. I'll post up the jetting that my bike had prior to the airbox removal in the jetting database, which might shed some light on your problem. I think for some specific jetting and bike setups, you're better off not removing the Kleen Air system.

Cheers,
Owen

Sling Shot Racing has this nice cap for the 250.

http://farm5.static.flickr.com/4075/4778111993_3e4ae3f2c6_m.jpg
Thats what I have. Make things nice and clean

Kelly, where you at? Would appreciate your advice on response #109. Thanks!

Finally had a chance to remove a shim, so I'm only running one now. Idle is back to normal and no need for the choke. However, I still have a noticeable flat spot below 6k. I also rode my buddy's bike with the same exact set-up, except he has 2 shims, and his pulls notably stronger at the bottom end. Any thoughts? Stumped.

idk. this mod is being done to help reliability right? but deleting parts in my mind makes me think it would negatively effect engine life.

has anyone had any problems after doing this?

It's actually being done to compensate for issues stemming from opening up the engine airflow with a removed airbox and/or aftermarket exhaust systems. If you're not having minor backfires/popping on deceleration, I wouldn't worry about it.

That said, I haven't heard much/anything as far as major engine failures that can be directly linked to this. Usually the problems people experience are changes to the jetting needs due to the removal of an airflow path. Sometimes people find their bike runs better with the Kleen Air in place. Some folks have bikes that are happier without it.

natek,

I think Momaru is spot on. If you've changed to an aftermarket exhaust and/or removed the airbox, then you might as well pull out the kleen air system before you start re-jetting.

If you have a completely stock bike, then I see no reason at all to remove the kleen air system, and doing so may indeed result in problems if you don't adjust your jetting.

When I bought my bike, it already had an aftermarket full exhaust, and had been re-jetted to compensate for that. When I pulled the kleen air system out, the bike ran significantly worse.

I have since pulled the airbox and the kleen air system and fully re-jetted the carbs, and now everything runs just great.

In other words, if you're doing a significant amount of work (mainly removing the airbox) and re-jetting, then you might as well pull it off, if it's on now and your bike is running well with the stock airbox, then it's probably best to leave it alone.

Regards,
Owen

i was kinda put on the fence about it after taking the time to read page 3. it makes sense that less air going into the engine would require some kind of a re-jet. i liked the idea of simplifying everything and having less things that could fail/ brake/ wear out..... also something to tinker with and talk about lol

i'll just follow along and see if this resolves itself.

Hey guys, so I was getting ready to do this mod but I noticed something different that the old owner probably did to the bike. First there isn't any small tube that runs from the 'vacuum controlled valve' to the 3 way T connector, only the 2 big tubes to the cylinder head and airbox.

Secondly, the 3 way T connector listed in the pictures.. one goes to the carb, one goes to the fuel petcock, and one goes into the fuel tank. I have no idea what that means, but since my setup is currently different from the instructions I don't want to really mess anything up. Will appreciate any advice, thanks!

hmm will have to look into this.

i had previously removed the kleen air system on the bike. Plugg'ed a couple of the hoses as you can see from the BB's used at the ends of the 2 hoses in the photo.

Installed a smog plate, and now bike doesn't want to run with the tank hooked up. Bike runs when it's hooked up to a gas container at the shop tho.

19642

I'm wondering if one of the hoses is suppose to be connected still?

The the nipple at the top of airbox is capped off with the supplied piece.

19643

Sounds to me like you removed the hose that runs from the vacuum source (on the carbs) to the fuel tank valve.

There is a built-in shut-off valve on the fuel tank that requires a negative pressure to open and allow fuel to flow. This negative pressure comes from the carbs. You'll need to reconnect the small hose that ran from the carbs to the fuel tank in order to get everything working.

Cheers,
Owen

I totally am lost on the hose routing

19644 19645

Can't remember which of the carb hoses went to the petcock

I don't even have my bike any more, so I can't really confirm which it is...

I've circled the valve on the petcock that needs to be connected, and the two that I was able to narrow it down to on the carbs. If the hoses go to anywhere else on the carbs, then it's not that one. The hose in question used to run to a T connector, then off to the petcock and the Kleen Air system. If you removed the Kleen Air system and the petcock is disconnect, then you must have a hose coming off the carbs that goes nowhere.

See the attached pictures... Where do the two hoses circled in red go to?

Cheers,
Owen

I had the hose from the front middle of the carbs goto the circled petcock photo

The other 2 circled hoses, those just goto the Othe side of the carbs

Ahh... sorry. I remember now. That is indeed correct the way you have it. You can attach the two ports indicated with the arrow directly to one another. That's the way I did it and it worked like a charm.

Are they well connected? Do you have a leak anywhere?

Make sure the hose is pushed fully onto the petcock and the carb.

If it's not that, then I really don't know. You might need to adjust your idle.

I had serious issues when I performed this modification (I went over them in detail several posts back) but installing a K&N pod filter an re-jetting solved the issue. With the stock airbox though, I had idle problems and times when I would completely lose power and the bike would stall.

Cheers,
Owen

I had that hose running to petcock

I think it's suppose to be a overflow and just run a open hose from it

Nope... you definitely have it right. The overflow tube is much farther up the tank and comes directly out the side.

From what I remember, you can bypass the whole petcock negative pressure valve by just setting that switch on the petcock to "prime". You might want to try that and just rule out any possibility of leaks in that hose. If the bike runs fine with that valve in the prime position, but doesn't run with it in the "on" position, then you can be sure your problem is likely a leak in the vacuum system.

Another thing to try is to adjust your idle. You may need to increase it a little to get the bike to run in a stable manner. You can also try your choke to see if richening up the mixture helps.

Cheers,
Owen

Tried prime and didn't want run that well at all. Going to check all the connections again.

Now that I look a little closer, I'm pretty sure you have a California bike with the significantly more elaborate Kleen Air system.

The pictures of your removed system don't look like mine at all.

Look closely at the first post in this thread, and notice that the normal Kleen Air system only has three hoses coming off it. One goes to the cylinder head, one goes to the carb, and one goes to the airbox.

At the bottom of that post, there are pictures of the California model with several more hoses and another box tucked away.

Based on the pictures you've posted I'm guessing that's what you've got, which requires a whole different procedure for removal.

Cheers,
Owen

Just wanted to give credit to the OP. This is my first post on this forum so as a quick intro, live in the DFW area and decided to pick up riding about 3 months ago as a new hobby, but more to save on $$ on fuel costs and went and purchased a new 2012 Ninja 250r and shorty took the MSF course and the rest is history.

My first mod was to change the exhaust as to stand out more and be heard... Didn't really do it for a performance increase. Like most, the exhaust began popping and backfiring and did start get on the annoying side. I decided to take the plunge and give this mod a shot, take in mind that my mechanical skills is very novice, but the instructions seemed pretty straight forward. Only thing that took me for surprise was that I didn't think I was going to have to remove the gas tank. Probably a good thing though or I may have decided not to attempt it, but after having taking everything apart, decided to keep modding.

The result ended with the popping/backfiring was greatly reduced, but not completely eliminated. I only tested it out for a short ride, but I'll see how well it worked on my ride to work tomorrow morning.

Thanks, kkim, for the write up!:thumbup:

Has anyone had any problems after removing the system and i mean mechanical such as to much pressure or blowing gaskets?

Has anyone had any problems after removing the system and i mean mechanical such as to much pressure or blowing gaskets?

no

My bike runs only as a track bike and it runs very well.

Bought my bike in Texas, 2012. Does it have the Kleen air system a well?

yup... they all have it as far as I know.

California bikes have a more elaborate version with a few more connections and another module involved, but I think all other versions are the same type as what you see in this thread.

Cheers,
Owen

Just a note but some bikes sold in other states are actually CA models. It's not uncommon for the factory to setup a few to many bikes as CA models then ship them off to other states in need more bikes.

so do I need to cap the crankcase "chimney" too?

Brining up an old thread.

Why is the airbox hose attachment blocked off?

Thanks,
Doug

Brining up an old thread.

Why is the airbox hose attachment blocked off?

Thanks,
Doug

It attaches to the clean air side of the airbox.

snorkel intake -> air filter -> clean air -> carbs


If you don't block it off, you run the risk of dirt getting into your carbs, because it by passed the air filter.

aha... didn't realize it was on the other side of the air filter.

Thanks,

Trawling up an old thread here. I recently bought a 1998 250 with 1100 miles that a title search showed had never been anywhere but TX (where I live), yet it had a CA tank but no CA emission equipment. Possible that the tank was a replacement but can't be sure. Plus the L side panel had the CA emissions hose diagram that suggests it was a CA spec bike.

I originally capped off the red line as suggested by many others on the forum, but didn't like the idea of that becoming a source of leakage. So I got on eBay and found a complete set of emissions for $33, went to the local auto parts store and constructed a 'T' line between the carbs and plugged it all up per the routing diagram. The Haynes manual suggests testing it by putting 20 mL fuel in the top of the separator and seeing if it makes it to the blue return. Everything seems to be working so far, so I have not done it.

Has anyone done something similar? If so were there any problems? Or am I the only idiot who actually re-installed emission control equipment in pursuit of 'keeping it original'?

Thanks! And thanks to all for this great forum which helped me figure this out in the first place!

Can anybody help me with the ca emissions version? I tried following OP as best as I could but as pointed out the CA model has some extra connections. I'm currently left with a hose out of carb to a T connection, one end capped, the other end to petcock. Air box and chimney are capped. My issue is with the gas tank connections. There are 3 connections on the gas tank. Only the overflow is connected. The other 2 are capped. Is one of the other connections supposed to go somewhere?

Hi all,

In regards to removing the kleen system. If you've done it, does it stop the bike from backfiring loudly when turning on? My bike does that from time to time and it sounds like a gunshot. I'd rather not wake up the whole street at 4:30am with it too...

This (https://www.ninjette.org/forums/showpost.php?p=92474&postcount=8) answered my question. Middle vent needs to stay open.

Hi all,

In regards to removing the kleen system. If you've done it, does it stop the bike from backfiring loudly when turning on? My bike does that from time to time and it sounds like a gunshot. I'd rather not wake up the whole street at 4:30am with it too...

Not sure that it does, but the backfire at startup (https://www.ninjette.org/forums/showthread.php?t=15025) is notorious with our bikes

Hate bringing up a VERY VERY old thread, but I always think it's best to had as much info in one thread as possible, as opposed to a hundred I pulled the clean air system, and after reading all the pages here I'm still slightly confused is it best to VENT this, or CAP it. Thanks!

I capped mine, didn;t want an opening into my engine.

Mine I put a little breather on.

This is what I went with...

This is what I went with...

Yeah like that but mine points straight up.