can a airbox be open to much?

2/23/2018 12:21pm Edited Date/Time 2/23/2018 3:48pm
I have the 2017 kx250f, i have cut the right side of airbox open where it has been blocked from stock (to control sound im guessing). i noticed the kawi in arena cross have two large holes cut in the airbox hidden under the side number plate on left side..i seen this on gavin faiths bike. thinking of doing it also but dont want want to much air flow seen as i have already opened the right side up
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BobbyM
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2/23/2018 12:27pm
Fuck no
seth505
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2/23/2018 12:29pm
Yes, if it causes the filter to get caked with dirt ASAP.
kb228
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2/23/2018 12:32pm
I suppose if you opened it and had it dyno tuned while you do it so it doesnt run lean you can go as far as you want. Im sure theres a limit to the benefit and a risk reward issue with dirt getting on your filter.
peelout
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2/23/2018 12:32pm
i cut the airbox out of all my bikes for my sick tricks, big whoop wanna fight about it

The Shop

Jeff alessi
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2/23/2018 12:33pm
Open it up all the way n back it (with vinyl I believe?) I can’t remember exactly what factory teams put there but it breathes n keeps dirt out. Also foam works too but we just use it to help pass sound.
Plugga
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2/23/2018 12:34pm
peelout wrote:
i cut the airbox out of all my bikes for my sick tricks, big whoop wanna fight about it
Do you plaster them in Monster Energy stickers bro?
40acres
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2/23/2018 12:38pm
You can open it up all you want, you're just going to get more dirt in your filter. Unless Of course you've got a bunch of motor work and a proper tune on a dyno. But otherwise you're not benefiting at all from an open air box.
disbanded
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2/23/2018 12:38pm
Airboxes are like gallbladders, useless!
2/23/2018 12:40pm
Open it up all the way n back it (with vinyl I believe?) I can’t remember exactly what factory teams put there but it breathes n...
Open it up all the way n back it (with vinyl I believe?) I can’t remember exactly what factory teams put there but it breathes n keeps dirt out. Also foam works too but we just use it to help pass sound.
thank you, i think ive seen the backing on justin hills bike to stop dirt/sound but alow better flow.
CarlinoJoeVideo
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2/23/2018 12:52pm
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the place, not smooth at all. We put the cover back on with a few holes in it and had gains over stock but smoother curve. So in my opinion on my KTM there is such thing as too much air.


40acres
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2/23/2018 12:52pm
JD#442_NZ wrote:
Can I just increase my fuel by swapping my rich cupler in
That would certainly be better than the green coupler, but no it really won't benefit that much at all. I'd find a local, reputable shop with the Kawi tuner and habe them map it for you at the very least. But I would feel way more comfortable with my bike on a dyno. The Kawasaki mapping tool is something you'd have to play with to get right unless they have some tunes that will work that they've already tested.
2/23/2018 12:58pm
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the...
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the place, not smooth at all. We put the cover back on with a few holes in it and had gains over stock but smoother curve. So in my opinion on my KTM there is such thing as too much air.


awsome feed back man cheers. do you remove back fire screen?
40acres
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2/23/2018 1:01pm
JD#442_NZ wrote:
awsome feed back man cheers. do you remove back fire screen?
Absolutely
2/23/2018 1:01pm
JD#442_NZ wrote:
Can I just increase my fuel by swapping my rich cupler in
40acres wrote:
That would certainly be better than the green coupler, but no it really won't benefit that much at all. I'd find a local, reputable shop with...
That would certainly be better than the green coupler, but no it really won't benefit that much at all. I'd find a local, reputable shop with the Kawi tuner and habe them map it for you at the very least. But I would feel way more comfortable with my bike on a dyno. The Kawasaki mapping tool is something you'd have to play with to get right unless they have some tunes that will work that they've already tested.
bugger my local kawi dealer isnt reputable and dosn't have a kawi tuner i no of or dyno. il ask if they have tuner.
Motox627
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2/23/2018 1:08pm
Anyone get a noticeable gain from removing the backfire screen?
2/23/2018 1:09pm
JD#442_NZ wrote:
awsome feed back man cheers. do you remove back fire screen?
40acres wrote:
Absolutely
thinking i need get my bike on a dyno, not only have i opend the air box i have removed backfire screen with no toil kit and a full fmf system i am running my rich map but dont want my bike running lean or have a messed up power curve
40acres
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2/23/2018 1:13pm
You've also got a PC air boot on there as well. So you're sucking in all kinds of air without the fuel to match. Definitely get her on a dyno.

MotoX627: Not really.
Motox627
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2/23/2018 1:18pm
40acres wrote:
You've also got a PC air boot on there as well. So you're sucking in all kinds of air without the fuel to match. Definitely get...
You've also got a PC air boot on there as well. So you're sucking in all kinds of air without the fuel to match. Definitely get her on a dyno.

MotoX627: Not really.
Good to know. I have always left them in just for that peace of mind, but have come across a lot of guys removing them... thx dude
2/23/2018 1:21pm Edited Date/Time 2/23/2018 1:21pm
40acres wrote:
You've also got a PC air boot on there as well. So you're sucking in all kinds of air without the fuel to match. Definitely get...
You've also got a PC air boot on there as well. So you're sucking in all kinds of air without the fuel to match. Definitely get her on a dyno.

MotoX627: Not really.
sorry man that photo is gavin faiths kawi i would love the pc air boot
40acres
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2/23/2018 1:26pm
Oh, oops. Thought that was yours. Either way, get a good tune.
2/23/2018 1:29pm
40acres wrote:
Oh, oops. Thought that was yours. Either way, get a good tune.
haha no worries. thanks will look into who can dyno tune around my town
2/23/2018 1:31pm Edited Date/Time 2/23/2018 1:32pm
Motox627 wrote:
Anyone get a noticeable gain from removing the backfire screen?
i felt a difrence but i done a slip on at same time...i dunno if it was both together that made difrenece or the slip on or back fire screen removal.It is a risk removing it i was worried at 1st but my bike hasn't backfired once in 80 hours.
RedDirtDog
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2/23/2018 2:50pm
Motox627 wrote:
Anyone get a noticeable gain from removing the backfire screen?
JD#442_NZ wrote:
i felt a difrence but i done a slip on at same time...i dunno if it was both together that made difrenece or the slip on...
i felt a difrence but i done a slip on at same time...i dunno if it was both together that made difrenece or the slip on or back fire screen removal.It is a risk removing it i was worried at 1st but my bike hasn't backfired once in 80 hours.
if you remove the backfire screen you should get a flame retardant air filter like the twin air powerflow kit, the kit comes with it own anodized frame and no screen
byke
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2/23/2018 2:50pm
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the...
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the place, not smooth at all. We put the cover back on with a few holes in it and had gains over stock but smoother curve. So in my opinion on my KTM there is such thing as too much air.


I think airboxes act like a capacitor, or an accumulator, in that they're a medium designed to maintain a constant supply. Open it up and you introduce turbulence/air pressure fluctuations, which is why a power curve probably wouldn't be as smooth as something with a stable air supply. All the pitbikes use little k&n/uni hose clamp type filters and you can see their curve is pretty rough in some areas too.
2/23/2018 2:57pm Edited Date/Time 2/23/2018 2:59pm
Motox627 wrote:
Anyone get a noticeable gain from removing the backfire screen?
JD#442_NZ wrote:
i felt a difrence but i done a slip on at same time...i dunno if it was both together that made difrenece or the slip on...
i felt a difrence but i done a slip on at same time...i dunno if it was both together that made difrenece or the slip on or back fire screen removal.It is a risk removing it i was worried at 1st but my bike hasn't backfired once in 80 hours.
RedDirtDog wrote:
if you remove the backfire screen you should get a flame retardant air filter like the twin air powerflow kit, the kit comes with it own...
if you remove the backfire screen you should get a flame retardant air filter like the twin air powerflow kit, the kit comes with it own anodized frame and no screen
yea im using no toil flow kit that comes with filter cage plus flame retardant filter and can get spacific air filter oil also that dosnt catch fire. i wouldnt try modifly stock filter cage its near impossible to remove that wire mesh
Bruce372
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2/23/2018 3:04pm
You can open it up all you want, but the engine will only ever flow as much air as the throttle body allows . Plus, mx bikes are hardly ever wide open.

A few half inch holes in the side panel is fine, but these people drilling the shit out of everything are kidding themselves imo
2/23/2018 3:05pm
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the...
I saw my KTM 250F on a dyno with the airbox cover off, it did increase in HP but the power curve was all over the place, not smooth at all. We put the cover back on with a few holes in it and had gains over stock but smoother curve. So in my opinion on my KTM there is such thing as too much air.


byke wrote:
I think airboxes act like a capacitor, or an accumulator, in that they're a medium designed to maintain a constant supply. Open it up and you...
I think airboxes act like a capacitor, or an accumulator, in that they're a medium designed to maintain a constant supply. Open it up and you introduce turbulence/air pressure fluctuations, which is why a power curve probably wouldn't be as smooth as something with a stable air supply. All the pitbikes use little k&n/uni hose clamp type filters and you can see their curve is pretty rough in some areas too.
great point, comparable with the husky vs ktm airbox situation, some like the powercuve of huskys smooth delevery provided by suffercation haha

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