air box ?

[Blazin400]

i have a ? bout my airbox. the owner b4 me drilled holes in it and took the snorkel off. there r 144 1/8" holes. yes i counted them, i was that bored today smoking a cig. am i getting enough air or do the hole need to b bigger.. any and all info will help

[matt14c]

Did he plug the hole the snorkle was in? With 144 holes if the hole is plugged your still getting enough air. I would get a new airbox and put the snorkle back on if your running stock bore or atleast not a high performance setup.

[IcutMetl]

When I had my 400ex, I had a Yoshimura slip on and left the lid on the box because I rode a lot of woods, plus wet and muddy areas. Now after having my 250R and putting an EHS airbox lid kit on it, I wouldn't have it any other way; perfect alternative to having NO box lid at all.

[Blazin400]

i'm almost 90% sure there is a bore kit in it cuz the motor is diff colors. theres a k&n filter in it. there is a spray paint can lid in the whole where the snorkel was. i was just curious cuz if it was gettin enough air or not...

[wrekd]

Originally posted by Blazin400
there is a spray paint can lid in the whole where the snorkel was.



Haha...Thats how i plugged my snorkle up too

[Pipeless416]

just an FYI, even with the 144 1/8" holes, you're actually getting less flow than with the snorkel. you're total area comes out to 1.77 square inches.. where as the most restrictive section of the snorkel (the opening above the gas tank) is what.. like a 1"x2" opening? which obviously comes out to 2 square inches..

[IcutMetl]

A cheaper alternative to a fancy lid setup is to buy those UNI Airbox vents; you drill 1" holes in your airbox, and pop these in...glue if you wish, and you're off. The little foam filters are removable for cleaning and oiling. I like my EHS lid better, but I still have a mess of those 1" vents available if you're interested.

[Blazin400]

how many more 1/8" holes do i need to drill to have the proper air flow

[IcutMetl]

Probably as many more as you can fit; I would personally look for a replacement snorkel and possibly another factory lid on ebay...cheap stuff...and start over.

[Pipeless416]

Originally posted by Blazin400
how many more 1/8" holes do i need to drill to have the proper air flow

each hole is .0123 cubic inches using pi(r)^2. 2/.0123=163 holes. i would just get another snorkel and put it on, along with the holes in the lid.

[Blazin400]

thanks mike for all the info... its greatly appriceated

[rigger]

Both my R and my wife's 400EX are run with no lids. I use well oiled UNI filters and have never had any problems. I have a buddy that had a 400EX to and it was always run with no lid since day one and never had a problem.

Now just to mention, I would feel alot better about running with lids or with a modded lid but for now, they are run like they are and have had no problems.

Just because I said that, this weekends ride will more than likely end with blown motors due to water intrusion. :eek2:

A lid is always safer but will not flow the air.

[Blazin400]

lol ya i won't run without a lid cuz i live in nw pa. alot of trail rides which include alot of water and mud...

[rigger]

I do like that outer wear lid. That is nice.

I wonder if it can flow enough air by itself to feed the motor. I took the snorkle off of my wife's 400 and my R does not have one either.

If that lid with the pre-filter could flow enough air, that would be nice for a woods ride. Trails are what I ride 99% of the time.

Only thing I would might worry about on it would be dirt cutting back on air flow. It would have to get stopped up just like an air filter would.

[IcutMetl]

I have both my snorkel on and that EHS lid. Between the two, I'm sure I'm not losing much if any. And I can also imagine the difference between my setup now and NO airbox lid is very negligable. I haven't been on too many rides yet, but it seems to keep water out very well (if you're not standing there soaking it with a hose, etc), and the air filter has stayed near perfectly clean so far.

I like this lid as opposed to the velcro-on kits you find pretty much anywhere else because it still uses the airbox lid seal, plus a rubber gasket in between the aluminum plate and airbox lid surface. I had 1" holes drilled in the lid before for the UNI foam airbox vents, and to me it just looked like crap...drove me nuts.

[Muzzgit]

I have run my 400ex without a lid since I had a pipe and K&N put on it, but after splashng through puddles the filter was getting soaked and the engine was spluttering .

I have now put the lid back on but I have cut out the the entire back half with a jigsaw so I still get good airflow but now water doesn't land on top of the filter, it just runs down the back of the airbox and out the drain.

After two weekends of riding, it works perfectly.

[IcutMetl]

Typically what I'll do if I know I'm going to be riding in a lot of wet areas is just pull the plug on the bottom of my airbox, and just stick it in the box or in my pocket.

[rigger]

On my last 400EX, I took the lid and drilled 1/2" holes down the right side of the lid and across the back of it just past where the UNI filter would stop. That way when a lot of water did get on top of it, it fell down the sides and not on top of it. It seemed to work very well.

I do kind of like the idea of cutting the back of the air box open and putting the lid back on. It really does make since. You would have a roof over the filter and sides but still get the flow you need from the front and back. If you punched a hole in the back the same size as the snorkel inlet, and put the lid back on, you would have twice the air flow and still have that lid to protect juck from falling on top of the filter. That would have to be enough air flow to the motor, or at least I would think it would be.

Or do a series of 1/2" holes across the back and line them up so they look nice. Might be better looking than one big hole and provide a little more protection at the same time. And I guess that is the idea behind this thread. More air flow and still have filter protection while riding the trails.

[jasonwayne222]

So i just had a crazy thought reading this thread. why dont you try stretching panty hose over the air box with the lid off.

It should act as a coarse screen and still get all the airflow u need. and if its not enough stretch 2 or 3 panty hoses over it.

I think im gonna try it on mine. I just removed my lid after jetting and cam and other stuff but havent taken it to the trails yet,

[jasonwayne222]

heres another idea thats kinda out there. how about a small spal fan, like real small, something that could be mounted to the front of the snorkel and pump air into the snorkel intake, then leave the lid on. it will move more air i wonder if it would equal the amount of air with the lid off

[Blazin400]

Originally posted by jasonwayne222
heres another idea thats kinda out there. how about a small spal fan, like real small, something that could be mounted to the front of the snorkel and pump air into the snorkel intake, then leave the lid on. it will move more air i wonder if it would equal the amount of air with the lid off



if don't have a snorkle on mine. the guy took it off and drilled holes in the lid.

but in other words the whole panty hose idea might work... i'll try and find some and try it

[fwm416ex]

I drilled a couple of 2.5 inch holes in the rear of the lid and then shielded them with a aluminum baffle,I also removed the drain plug on the bottom of the box.

Has been working trouble free for years,even on the wettest trails and snow conditions

[fwm416ex]

Another shot

[06 Honda 450R]

i love the natty can on the shock cannister


Originally posted by IcutMetl
When I had my 400ex, I had a Yoshimura slip on and left the lid on the box because I rode a lot of woods, plus wet and muddy areas. Now after having my 250R and putting an EHS airbox lid kit on it, I wouldn't have it any other way; perfect alternative to having NO box lid at all.