Airbox lid mods

[Muzzgit]

Tacked on to the end of someone else's thread is a discussion about taking off airbox lids, filters getting wet, cutting holes, what to do?

I run the usual set up.....no airbox lid...K&N...jetted...slip on...

Recently I had a few rides on really wet tracks and have had my airfilter get completely soaked (like my socks!), to the point that the bike coughs and splutters.

I decided to cut out the rear 1/3 of the airbox lid and put it back on, so that if I do hit some water at speed it will splash up under the seat but won't splash directly on the airfilter, but still aiming for as much airflow as possible.

Last week I had the bike back to the workshop for re-jetting and dyno after run-in with new piston (406) and ported head and hotcam.

Brett at the workshop ran the dyno with both the partial lid and no lid at all and there is a difference.

Besides getting a few ponies more (now 35.4) after re-jeting, having the partial lid on did have a very slight effect on power, (down about 1 horse) and it runs a little bit rich.

The upside is running a little richer won't hurt, I probably wouldn't notice the drop in power and on winter rides I'll take that loss in place of a dry airfilter !

[honda400ex2003]

good to hear that it worked out for you. just another option for you, is the ehs lid, it keep out quite a bit of water. I havent actually had any in my box since i started running it. I have hit some deep puddles also with it. I have been soaked through the shoes and all with no problems. Steve

[Muzzgit]

I guess my point was to let people know that even a small difference can change the mixture. Same as fittng an EHS lid, the jetting may need to be altered.

Like taking the lid off a stock bike will make it lean.

[honda400ex2003]

oh my appologies if i seemed to tell you differently but i think this a good idea with the lid. Can we get some pics. I have too witnessed the jetting differences, i used to just put my stock lid on for the winter to get it close. it actually made it too rich for the winter to go from summer setting. it makes a huge difference in air flow with it on and off. steve

[MidnightBlade]

outerwears makes an airbox cover and kn makes the powerlid from what ive read they are about the same but the outerwears is $10 and the kn is $40-80 but i just run with the lid on cause icant get it off thanks to the liscense plate but im still runing the sock filter so i cant get it wet or im screwed

[rooster300ex]

U need a prefilter if water hits it it will run off like on a ducks back

[honda400ex2003]

lol, and agreed. outerwears are really nice. steve

[MidnightBlade]

im getting a kn soon then ill get a pre filter

[rooster300ex]

Originally posted by honda400ex2003
lol, and agreed. outerwears are really nice. steve

i don't know if u have seen madea goes to jail, but there is a part in that movie where she is talkin to Dr. phil and he said why don't u just let things like that run off your back like a duck, and she said cuz I ain't no damn duck. lol

[tri5ron]

Originally posted by Muzzgit
I guess my point was to let people know that even a small difference can change the mixture. Same as fittng an EHS lid, the jetting may need to be altered.

Like taking the lid off a stock bike will make it lean.
True that.
I made a outerwears lid for mine, and it has a greater coverage, (more open) area than most of the other homemade lids you see on here. here's a pic...
http://i111.photobucket.com/albums/n148/tri5ron/03%20400ex/IMG_0136.jpg
http://i111.photobucket.com/albums/n148/tri5ron/03%20400ex/IMG_0137.jpg

yet while doing my dyno runs, you could still see the difference with my modified lid on, or with it removed completely.
Granted,... it wasn't a huge difference, but it was noticeable, on the dyno.

[grassman]

where is a good place to buy the prefilters... besides e-bay.

[MidnightBlade]

try denniskirk.com, rockymountain.com, or traxms.com