You need the lid to hold the air filter in on a stock airfilter... you either need to cut a hole in the lid, or get a new filter and scrap the lid.

 

a good idea, get air box vents, they fit 1in holes and totally filter ait. put a bunch of those in ur lid. u wont need to rejet for just that and u will get a little kick.

 

that is what i thought, but the machine is not drivable with the lid off. i have been complaining that my machine does not have enouhg sack, i wonder if the 04 raptor is way under jetted from the factory. you can not rev the motor over 4500 with the cover off.

 

It takes more than removing the lid, to get more power.
What is needed, is to move more air thu the motor, with the proper amount of gasoline.
So to get a meaningful improvement, the intake has to flow more, the exhaust needs to flow more, and the proper amount of gasoline needs to be added. So, if you pop the lid off, and rejet, eventually youll run into what the exhaust can flow out, and progress stops. Usually, its a package deal, goota deal with all three. Theres a bit of reserve capacity built in the exhaust, but youll hit the limit before any meaningful horses are made.

 

Ok All Yamahahaulers, here is the scoop[ I'm a Yamaha pass tech.... the motor need a air space quality to help keep the motor air pressure a a certain pressure if you remove the box or even remove it completely the bike will run like this... it will cut out with fast quick full throttle, as well with mid full throttle it will cut out, it does not matter you can change carb jets til you die it will do the same, freinds I'VE BEEN THERE i'VE DONE IT IT DOES NOT WORK YOU NEED THE BOX PLEASE KEEP YOUR BOX YOU WILL DO YOURSELF A FAVOR, ROCK ON DRILL HOLES ONLY 25% ONLY ANY QUESTION PM ME.....JIMBO

 

BUT, if you have an aftermarket exhaust then the air coming in can be greatly increased because of the ability to flow more out.

In otherwords, dont increase flow over 25% with a stock pipe.

 

Hey Jimbo, I got rid of my box completely and didnt notice any ill effects. Im actually running stronger now than with the box. I can see that you would need some air for running maybe 1/4-1/2 throttle but once your running WOT, you would suck the air out of that box pretty quick and would only be getting air by a small 3in opening. This is where I see the "no airbox" intake would be most beneficial, since it has all the air that it might possibly need. Also the twin filter setup has more surface area than the stock filter, which would aloow for more air flow and better filtering. I dont want to bash on Yamaha techs, but I went to my dealer to get the brake recal on my raptor, and I saw a yamaha mechanic put oil on the INSIDE of a K&N filter and I was always under the impression that you shouldnt oil the inside, just the outside....I would recommend Figleone to just cut the lid in half so it will still hold the filter and jet up, that should solve the problem.

 

Ok YamahaHalers you asked I told you yes some of you guys can't or won't relize you trike is runing right But I tell you right NOW if you remove you lid or box totally it will not run to alitamite preformace I don't care what some say . yamaha has to have a air restriction to otimize the air flow if you don't believe so be it it's your quad it's you loss if you want a great running quad PM me and I will give you the run down ups and downs I owned 2 warrors and one banshee I know they ran the same on boxes and jets, lets get it right lets get you bike running correctly I will help you will be totally surprised how well it would run if you only listen young tikes.

 

Well it makes absolutely no sense to me. I remeoved my lid, i had to jet up a few sizes. More air + more fuel = more power. I don't see anything you can say that will change that. If i put my lid back on and went down a few sizes i know I will go slower because i have tried it. I ran the bike with the lid, and propper jetting, and without lid with propper jetting.

 

Yep, When I took the lid off and re-jetted I thought I was on a different quad. Scarry fast for me, I had to get used to riding with that much power.