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Old 02-08-2013, 09:55 PM   #97
Joined: Jul 2005
Location: Traveler
Oddometer: 5,218
Originally Posted by Young-gun-640 View Post
Hi Bill, I'm confused now.... I may be misunderstanding what people are talking about when they say they are doing "the airbox mods"... I was under the impression that the go is not to replace the filter with a screen but rather just to replace the solid plastic side panel with a screen to allow more air into the airbox which then gets filtered by the nicely oiled air filter, am I correct?

From what you said above, it sounds like you're saying that the side panel is hollowed out as CSF has done, a screen put in the side panel as the only means of filtering the air and then no actual air-filter used to filter the air once inside the airbox... if this is the case then I'm with you, I wouldn't be doing that
There is an old debate about the airbox and the BST40 diaphram carb that stems from from some dyno work done at the Sommers KTM dealership in Austria. They opened the airbox on the side an installed a rectangular screen and left the snorkel in place. They rejetted or re-needled, can't remember and got some extra horsepower on the dyno.

Someone got the idea to remove the snorkle and cut the snorkle hole bigger to accomplish the same thing. This had the advantage of keeping the ingress of water at a higher level and also dust is forced to enter at the seat level.

When more open mufflers were used some of us reasoned that more 'air' was needed from the intake end of things.

What I am saying is if you remove the snorkle and cut the hole bigger, don't block the opening with fine screen because you will restrict the flow of air into the airbox.

With the airbox closed on the sides and open on the top(enlarged hole, no snorkle, no screen) the system runs fairly clean even in heavy dust. Whe you pull the foam filter to clean it you will find dirt on the top but it will be clean on the bottom.

If you are far from home you can remove the filter and wash it clean with gas from the tank. It will dry quickly in the sun. Knock off anything loose after it dries and oil it with engine oil.

The engine will run nicely and thank you especially if you have a bunch of pavement to cover crusing back to the crib.

'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
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