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courts
16th September 2008, 16:28
Does increasing the air flow into the filter increase power.??
If so, is there a way to optimise flow without opening it up too much and getting all kinds of crap in your airbox.?

B0000M
16th September 2008, 20:41
depends on the airbox, if its pretty closed up like a CRF-X airbox then yeah opening it up will benifit you and ther is power to be had from doing so.

on the other hand, you'll have to clean your air filter more often. - as more air gets to it easily so does more dirt

CRF119
16th September 2008, 20:43
Yes the more air avalible the more power you can get out of your bike. You may have to rejet it.

Mods on my CR125 for more flow where.

Bore Carby Out and re polish
V-Force Carbon Reeds. (Grinded abit out of that to increse flow)

On my CRF450 i was told to remove the steel mesh from behind the foam air filter but i think this is a bad idea as this provides support to the foam.

His CRF450 did have more top end power then mine but i dont think its worth the risk.

The Motard bikes use a hi flow filter and cut the air boxes and that helps but more flow means more shit will go past.

As far as cutting big holes in the air box on the new motor x bikes i dont think it helps. My mates have FMX grab handels and makes no diff.

On Bikes with the small Air boxes Like the XR200 etc i went to Farm and trail in TA and picked up a spare Air box just to hack up. I found making the hole into the Air box twice the size made a small differance but you do get more dust into it.

What bike have you got?

courts
16th September 2008, 20:54
Yes the more air avalible the more power you can get out of your bike. You may have to rejet it.

Mods on my CR125 for more flow where.

Bore Carby Out and re polish
V-Force Carbon Reeds. (Grinded abit out of that to increse flow)

On my CRF450 i was told to remove the steel mesh from behind the foam air filter but i think this is a bad idea as this provides support to the foam.

His CRF450 did have more top end power then mine but i dont think its worth the risk.

The Motard bikes use a hi flow filter and cut the air boxes and that helps but more flow means more shit will go past.

As far as cutting big holes in the air box on the new motor x bikes i dont think it helps. My mates have FMX grab handels and makes no diff.

On Bikes with the small Air boxes Like the XR200 etc i went to Farm and trail in TA and picked up a spare Air box just to hack up. I found making the hole into the Air box twice the size made a small differance but you do get more dust into it.

What bike have you got?

Got a wr250f prob same sort of box as crf250x.
Not too keen to remove mesh but i thought by adding small holes or something . dont wanna compromise getting shit in engine tho. do my air filter every ride and use thatsuper sticky oil yammie do.

B0000M
16th September 2008, 20:58
i found removing the mesh and cutting holes in the airbox to match an R airbox on the X made a difference. did both at the same time. but if you look at how restrictive the airbox origially is its amazing how the bike even runs at all

CB ARGH
16th September 2008, 21:12
To stop the crap from getting in then just get a pair of stockings and fit it over the whole box (or just where the air comes in). Great for on sandy tracks too.

monchopper
18th September 2008, 21:11
On my XR400 I opened it right up put a Hi flow K & N filter on . Then cut some Skid Plate Foam (http://www.cyclepages.com/ProductGroupDisp.aspx?ProductGroupID=4002384)to the size of the opening of the air box. Soak the foam in filter oil.
The Foam acts as a pre-filter and gets most of the dust, the K & N gets the rest and the engine can breathe.
I got the idea from http://www.thumpertalk.com/forum/archive/index.php/t-104858.html this article on Thumpertalk.

You'll almost definitely need to rejet. Go a couple of sizes up on the Main for starters. Buy some different size jets and trial and error them.
Eg. On my XR I went from stock Main #152 Pilot #42 to Main #160 Pilot #60. Google it, someone has already done this so use the net.