Additional airbox mods. What is to be gained/

I was wondering what are the gains of modifying an airbox as shown in the following pics. I never ride near water, hence deep rivers will never be a problem for me.

How would these mods affect the jetting?

airbox mod 1

airbox mod 2

airbox mod 3

It might make your jetting lean, but the more air available the better. Should gain a little on the top end.

Your next step might be to take out the mesh from the cage. This boosts airflow considerably. Think about how much surface area that mesh is taking up.

Holly Crap Dude :thumbsup:

That would be enough air for a big block chevy!

Yea on the leaner but do you think one cylinder can suck up that much air?

I can see a modest hole in the top but,,, looks like termites...over kill !

waaaay too much :bonk: i'd say just riding that in the rain would be an issue :thumbsup:

Man, you went to town with that one.. :thumbsup:

wow theres no way i could do that in ohio. that box would be filled with water and mud , not good :thumbsup:

04 WR450f

04 Crf150f

Put Down The Drill... :thumbsup:

on the bright side,he shaved off about a 1/2 lb :thumbsup:

Air box mod #1 is all you need patch the others up or buy a new box and do it again. :thumbsup:

anybody have any realistic pictures of a 99 air box thats been done? Thanks.

Put Down The Drill... :bonk:

......AND BACK AWAY WITH YOUR HANDS UP! :thumbsup:

Mmmmm. There seems to be a bit of a general consensus developing here. It strangely contradicts the expert advice that I was given by Marcus Moberg. He said that the more I cut out of the airbox, the faster my WR will go. He told me he had the fastest WR in the US, so I trusted his judgement. I figured that with the 3 World Enduro Championships and World Land Speed record under his belt, he would know what he is talking about. :thumbsup:

On another note, thanks for all your advice on the matter. :thumbsup: Now lets see, where is that yamaha part number for a new airbox.

:bonk:

we can call that the "moberg mod" :thumbsup:

Mmmmm. There seems to be a bit of a general consensus developing here. It strangely contradicts the expert advice that I was given by Marcus Moberg. He said that the more I cut out of the airbox, the faster my WR will go. He told me he had the fastest WR in the US, so I trusted his judgement. I figured that with the 3 World Enduro Championships and World Land Speed record under his belt, he would know what he is talking about. :thumbsup:

:bonk::thumbsup::eek::p:worthy::cool::prof::lol::lol::worthy::worthy::worthy::worthy::banghead::banghead::banghead::banghead::banghead::banghead::foul::foul::banana::banana:

We all love our resident TT mod expert MarcusMoberg!

without doing the now famous "moberg mod", where would be the best place to open up a 99 wr400 airbox a little bit. I do ride in water (rain) sometimes and a puddle of mud every now and then so i dont want to make swiss cheese but a little somewhere. Any suggestions on the beast area of the box. pics welcome of course. Thanks guys.

I have to say, that I did the 12 hole drill out on my '03 250 and it seemed to make a significant difference. I never had an issue with rain or mud.

the '05 450 has just met my hands. I am yet to even ride it yet. It has most of the standard mods done though.

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