airbox cover/snorkel on stock EFI models
 

Hey!


Got my KLX250S 2012 EU (with EFI, not carbureted) about a week ago. Have been reading up a lot (partly because I don't have my driving license yet :D).
So today when I added a cigarette lighter socket to the bike, I also took off the airbox cover, just to see what difference it made.
Could not notice any more power, but the sound sure was more louder and different. Did not ride much tho.
Since I have the EFI, I think the ECU is supposed to regulate everything automatically and if the bike was begging for more air, there should be at least a slight difference in power.
Is there any proof removing the airbox lid automatically gives more horsepower to the EFI bike?

And another question...
Let's say some water does get in the airbox, what would it do the bike?
I mean what am I risking with when riding without the cover?

Also there was this big yellow sponge, which made me think that even if some drops of water got in there, it would probably vaporize thanks to the airflow.

I probably might put it back anyways cause of the noise and try to get a KDX200 snorkel.

On the advantage of removing the lid, there is some advantage if you have the other elements in place to take advantage...a free flowing exhaust and a fuel mixture optimum for conditions. Many don't like the added sound. If you don't modify the exhaust, I don't think you really gain much if anything by removing the lid. The FI should have the latitude to deal with that.

On water in the airbox, the frame rails and seat panels do a pretty job of keeping water directed away from any straight shot to the airbox with the lid off. The snorkel just makes it harder and is probably more sound control than anything. To get water in our airbox, you're just about going to have to ride in a depth that actually exceeds the airbox top...or fall over in the water. If by whatever method you get water in our airbox, it will wet the air filter if it's in there in a decent quantity for more than a couple of seconds. There's a drain in our airbox that will fairly quickly allow the water to run out if the bike is upright. That's why it's important to kill the engine ASAP in a water tipover and stand the bike upright ASAP. With a wet filter, the engine has the ability to pull that water out of the filter if you get it running. Depending on how much water mist it pulls, it can kill the fuel/air ratio and quit running. It's also possible to draw enough water into the cylinder and actually hydraulic lock causing major engine damage...bent rod, etc. If you wet the filter sufficiently, it's better to pop the seat off, remove the filter, and squeeze all the water you can out of the filter.

When you say a "yellow sponge" I'm guessing you're referring to the air filter itself? You don't want that sponge to soak up a bunch of water.:D

Too bad the buttplug is welded on this model. Would love to remove it. :) Don't have the resources to get a new exhaust atm. -__-
And I can't drill it either, because that would cancel the warranty.

Don't bother drilling the stock exhaust, it only makes the spark arrester useless. You can cut the end cap off and replace with something with a bigger outlet though.

And i don't know if the ecu will be able to handle the added air of removing the airbox lid and new exhaust without some kind of fuel management add on. AFAIK most FI bikes use a speed/density type of fuel injection management system which is blind to increases in air volume.

Basically the engine management system is looking at a set of pre-programmed tables for how much air to expect at whatever the measured temp of the air coming into the engine in relation to how much load is on the engine. Since these table would have been programmed for a stock bike, increasing the amount of air moving into the intake is not going to translate into increased fuel.

In order to change the variables in these tables you need a power commander or the like.

Of course i could be totally wrong on this. Maybe one of the members here who is more well versed in the efi models can chime in.

Looking at the marcelino camshaft mod dyno graphs, it looks as if removing the lid on the EFI models can give us a minor HP boost, without doing any other modifications. Unless he's just not mentioning that he also has an ECU controller, which seems doubtful from what he's saying. :)

do the FI bikes use the same air intake (snorkle) setup the carbed bikes do?

yes, they do. :)

pulling off your air filter lid or fitting a performance pipe will make your EFi bike lean....basically. Will feel like the same power but running rougher & hotter.

You will need to fit a performance ECU or a piggyback controller like a power commander V, juice box or EJK. These controllers will allow you to add more fuel to the engine when you let more air in...example, when tinkering with the air box.

This thread is very informative of PCV:
https://www.kawasakiforums.com/forum...250-efi-35678/

This thread is as long a war & peace!! It talks about all the controllers:
https://www.kawasakiforums.com/forum...-klx250-36083/

Good luck & enjoy......there's a lot of reading ;)

Thank you so much, Joel.
I've actually read/skimmed both of these threads, but never found the answer to my question you have now answered.
Gonna go to the garage and restore my bike to stock right now. :)

I guess there's no free mods (except the 5th & 6th gear de-restrict) for the EFI bike then. =(

If you ride mostly trails, change your rear sprocket to 49t and chain to 110. Its like having another bike.