Airbox Holes

[RadRacer]

I've read in many places that a good way to get a little gain is to drill holes in your airbox lid. Exactly how much gain do you guys get form this, and does water ever get into the box? Lately, when I've been riding, It's been pretty muddy, and we've gone through quite a few puddles/ponds, so I don't wanna do it if it'll screw up my engine.

[300exOH]

Drilling holes will gain 1-2 horsepower butit does let stuff in now and then. Check out GT Thunder for their velocity stack. I have a similar setup and it works great. You may have to clean your filter more in dusty areas though. You may also have to rejet 1 or 2 sizes to gain full advantage of opening the airbox.

Heres a pic of mine. It's basically just a tube that goes through the lid and directs water/mud away from the filter.

[RadRacer]

OK Thanx. how much does the velocity stack cost?


EDIT- Found them, they cpst $20, btu I might go and build my own, or not even owrry about it. I have a SuperTrap exhaust coming, and I was wondering how much HP gain I can expect from that. Also, if I drilled the holes in the airbox lid, would I notice any difference in speed? If so, how much? I realize that it gives you a couple more HP, but I don't really know how much more speed you'd get from one HP....

[300exOH]

Not sure how many horsepower the exhaust is worth. I'd say around 4-5 at most. You'll notice a big difference as long as you rejet properly. As far as top speed goes you probably won't see more than a couple MPH but you'll accelerate much faster.:devil:

[RadRacer]

Originally posted by 300exOH
Not sure how many horsepower the exhaust is worth. I'd say around 4-5 at most. You'll notice a big difference as long as you rejet properly. As far as top speed goes you probably won't see more than a couple MPH but you'll accelerate much faster.:devil:

OK Thanx. Now i need to go buy/make some of those velocity stacks....

[400exrider707]

If you have ever read a 400ex pipe shootout you would notice that a pipe/filter with no airbox lid combo is good for 1 -2 horse max. It certainly feels like a LOT more from seat of the pants, but thats the facts.

[RadRacer]

Originally posted by 400exrider707
If you have ever read a 400ex pipe shootout you would notice that a pipe/filter with no airbox lid combo is good for 1 -2 horse max. It certainly feels like a LOT more from seat of the pants, but thats the facts.

And as you can probably tell, I've never read a 400EX pipe shootout! I've talked to my dad about it, adn he's thinking about it, so I might build them this week-end........HOPEFULLY!

[300exOH]

Originally posted by 400exrider707
If you have ever read a 400ex pipe shootout you would notice that a pipe/filter with no airbox lid combo is good for 1 -2 horse max. It certainly feels like a LOT more from seat of the pants, but thats the facts.

We're talking about a 300ex though.:rolleyes: I did say 4-5 HP at MOST. But you may be right. I haven't seen any dyno sheets for a 300ex. I'm only going by what the pipe manufacturers are claiming. Actually they claim 6-7HP increase.:eek2:

[RadRacer]

Thanx for the help guys. I'm still not sure if my dad will let me build them or not, but once he decides, I'll let yall know. I hope he does, cuz We're gonna go riding May 8th, and my uncle, cousins and aunt are coming, so I'd kinda like to show off, if ya know what I mean!