[scooter]

The stock air filter on the Vulcan 900 is very restrictive, as most of you know, so I will likely upgrade to a Baron BAK soon. Even though the bike runs great and gets 50 mpg, I'd lie to improve the breathing. I'm told that the metal screen on the filter blocks 1/3 of the airflow, if that's true what harm is there if the screen is removed (would be like an ordinary filter).
Also, I always thought the bike was factory tuned to run lean, now I'm told that it runs rich so air air filter upgrade should improve combustion without and EFI re-tune, correct??
I welcome any and all feedback.

 

[nadman]

Stock air filter

Go ahead and cut off the metal mesh screen on your stock air filter. It's like adding 200 cc's. to the engine. Throttle response is greatly improved and highway acceleration is way better for when you just have to get around someone. More air equals a happy engine and a cooler running engine as well. To a point, if the engine gets to much air it will run to lean and to lean is going to run to hot. My 900 seems to like the missing screen and I like the slightly improved sound of the engine as well. If I had to venture a guess, I would say that the screen cuts off a good 40 % of the air flow. My bike likes the change and so do I.

 

[Toddster]

Sorry if this sounds dumb, but what screen are you talking about? Also if you cut out the screen could the motor run the risk of sucking in a stone or something?

Would you be willing to post a photo of it?

Thanks

 

[nadman]

Air filter mod

On the front of the 900 cc. Vulcan air filter is a metal screen, a thin membrane that has a bunch of holes in it to allow the air to flow through the paper element covering the throttle bodies. There are five plastic rivet like studs that hold the screen on to the body of the air filer. I used a utility knife to remove the tops of the rivet like studs and then lifted the screen off the air filter body (frame). I have no way to send a picture of the screen but if you remove the air cleaner cover to expose the air filter it is the shinny metal part of the air filter with all the holes in it. It's right in front staring at you. As far as I can tell there is no way that a rock or other object can penetrate the paper element to damage the throttle bodies. I have even removed bugs that have some how gotten behind the paper element but was trapped in the pleated portions of the air filter. I really don't know what purpose this screen plays in the overall scheme of things but it really restricts the amount of air flow. Time will tell but I'm will to bet this is a cheap fix to the air flow problems plaguing all modern engines thanks to the E.P.A. I'll keep you posted on my findings.

 

[Toddster]

nadman, Thanks for the info!

I know what I'm going to do tomorrow......

 

[liquid540x]

Doesn't the screen hold the filter in? Is it still secure when you cut the screen off?

 

[rs900c]

I happen to have just had my air filter apart and removed the screen, so I have attached pictures. The picture with the filter on the bike is the side where the screen used to be before removal. This screen does not provide any mechanical/structural support for the filter. The filter is molded onto the plastic and is supported down the middle. The pleats in the filter are very stiff, and there's no was the engine will provide enough vacuum to pull the filter element through. I'm not sure what Kawasaki's purpose was but it won't hurt anything by removing it and it will improve airflow.
I believe that most new cars and motorcycles are designed to run more on the lean side for EPA purposes. If it was designed to run rich it probably wouldn't pass EPA emission standards.

 

[Mailman]

Removing the metal cover sounds interesting, but man, I sure hope it wouldn't lean out the engine to much.......be a pisser to burn it up due to being too lean.

 

[sandman20]

FYI guys, that screen is not some EPA cooked up item for emissions. It is called a backfire screen and most 4 strokes, particularly singles have them on the air filter. It is to help prevent your air filter from catching fire in the event your engine backfires through the throttle bodies. With all due respect, I have yet to see a dyno chart published proving that these mods do anything for HP gains. If anyone knows where I can find one please post a link as I'd love to see it. IMHO, I do not believe you are going to gain a heck of a lot without spending some cash on pipes, intake kit and fuel management system for the 900. It's not like an ancient air cooled Harley where decent gains can be made with intake, exhaust tweaking. The engine is a very efficient liquid cooled 4 valve engine. Any gains even throwing $$$ at it would most likely be very modest.

 

[SouthBend Vulcan900]

Ok how does this affect things if you have done the debaffle?
If I remove the screen do I need to then have the computer redone?

Just want to make sure I wont mess anything up having already done the debaffle.

 

[sandman20]

Depends, if you like your bike going up in flames.........take the screen out......lol. I personally don't feel I know more than Kawasaki designers and engineering staff.

 

[Mailman]

Depends, if you like your bike going up in flames.........take the screen out......lol. I personally don't feel I know more than Kawasaki designers and engineering staff.

You and I both.

 

[scooter]

That's the first thing that makes any sense. I'm sure the screen blocks some airflow since it's a safety barrier I'm leaving mine on. I'm sure removing it doesn't make that much of a difference. If I want more performance I will likely go with the BAK.

 

[silenthill]

reviving this thread....I was always curious about removing that metal mesh......are people still doing it?

 

[txmedic712]

reviving this thread....I was always curious about removing that metal mesh......are people still doing it?

I'm curious about this too after reading it. Maybe I'm just not understanding, but the fiber pleat material is there regardless of the metal screen being present or removed. Exactly how is this screen going to stop the element from catching fire? If the bike were to backfire through the intakes the fibers would be exposed to flame regardless of the screen. It seems to me that the screen is an inefficient protection from this threat. Maybe I just don't understand.

Also, the K&N filter does not possess such a screen. It does have a fine mesh screen over the filter element to protect the element itself but no metal screen like the factory element. Maybe someone can explain this better to me. Has anyone removed the screen and had their bike catch fire??

 

[silenthill]

I'm curious about this too after reading it. Maybe I'm just not understanding, but the fiber pleat material is there regardless of the metal screen being present or removed. Exactly how is this screen going to stop the element from catching fire? If the bike were to backfire through the intakes the fibers would be exposed to flame regardless of the screen. It seems to me that the screen is an inefficient protection from this threat. Maybe I just don't understand.

Also, the K&N filter does not possess such a screen. It does have a fine mesh screen over the filter element to protect the element itself but no metal screen like the factory element. Maybe someone can explain this better to me. Has anyone removed the screen and had their bike catch fire??

Agreed....first thing I noticed was aftermarket such as kn don't have any mesh....I just changed my air filter and I don't particularly like the restrictive nature of the steel mesh cover....seems like our 9's have hard enough time breathing now.....

 

[pacomutt]

I'm curious about this too after reading it. Maybe I'm just not understanding, but the fiber pleat material is there regardless of the metal screen being present or removed. Exactly how is this screen going to stop the element from catching fire? If the bike were to backfire through the intakes the fibers would be exposed to flame regardless of the screen. It seems to me that the screen is an inefficient protection from this threat. Maybe I just don't understand.

Also, the K&N filter does not possess such a screen. It does have a fine mesh screen over the filter element to protect the element itself but no metal screen like the factory element. Maybe someone can explain this better to me. Has anyone removed the screen and had their bike catch fire??

The screen is on the fresh-air intake side, not the engine side. If the engine backfires, the resultant pressure from that burp could blow out part of the paper element if the screen wasn't there to hold it in place. Then when the engine was restarted, or running normally again, the airflow could pull the ruptured paper into the engine. That wouldn't be good, would it?

 

[silenthill]

The screen is on the fresh-air intake side, not the engine side. If the engine backfires, the resultant pressure from that burp could blow out part of the paper element if the screen wasn't there to hold it in place. Then when the engine was restarted, or running normally again, the airflow could pull the ruptured paper into the engine. That wouldn't be good, would it?

Since u put it that way....lol.....
But, the KN....No mesh because?

 

[pacomutt]

Since u put it that way....lol.....
But, the KN....No mesh because?

Don't know. Maybe 'cause the K&N media has more elasticity and can survive a backfire better than pleated paper? Or maybe 'cause K&N doesn't have to worry about protecting Kawasaki's engine throughout at least the warranty period? Use aftermarket parts? You be on your own!

 

[Sojourner]

Ok how does this affect things if you have done the debaffle?
If I remove the screen do I need to then have the computer redone?

Just want to make sure I wont mess anything up having already done the debaffle.

How far did you go debaffling? Even without the screen the paper filter presents resistance to the air flow. Your OEM ECU cannot be adjusted so if you determine you are running too lean then an aftermarket fuel management system would be needed. Inspecting your spark plugs gives you a very good idea how rich or lean your engine is running.