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should i take off my air box lid
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Posted by: yoshimurakfx400

i have a 03 kfx400 and i was wondering if i should take of the air box lid or not?

Posted by: spincr4hire

You've got a Yoshi pipe, right? have you rejetted the carb yet?

Posted by: Crowdpleaser

depending on what type of terrain you ride in, you dont want alot of dirt or water in your airbox, i would recommend the k+n powerlid or the outerwears lid. the outerwears lid is a airbox lid with an outerwear as the lid. the k/n looks just about the same but with their filter material as there lid. both would reduce dirt and water while giving u the benefit of way more air flow

Posted by: yoshimurakfx400

i have a yoshimura slip on and i havent re jeted it yet, i called yoshimura and they said i shouldnt have to re jet it

Posted by: spincr4hire

quote:
Originally posted by yoshimurakfx400
i have a yoshimura slip on and i havent re jeted it yet, i called yoshimura and they said i shouldnt have to re jet it

that doesn't sound right

Posted by: Billdog350

I agree with spincr4hire, if you don't need to rejet it then you're probably not gaining much power. Usually a good pipe will give you more flow which leans out your motor, which requires richer jetting.

As far as the airbox lid, I strongly recommend it. If you're doing water crossings you'll want to have the lid handy or find a way to avoid them. I made my own outerwears lid and it works slick as heck. Its slightly water resistant and keeps big mud and dirt out nicely. Removing AND REJETTING gave me tons of power down low. However, if you don't jet you'll find that the thing barely runs above 1/4 throttle. I had to rejet immediately or it wouldn't run worth beans.

Posted by: yoshimurakfx400

im goint to check my plug tomorow and see if it is the rite color if its not the rite color ill get back with u guys

Posted by: Billdog350

After checking your plug, make sure to check your jetting against other people with the same setup. I can't imagine a company not telling you to rejet with an aftermarket pipe.

Posted by: TC426EX

take it off and rejet

Posted by: Redline

Pull the lid and rejet, I have the yosh too and it makes a HUGE difference

Posted by: nemesis

Yoshi recommeds a 152.5 main jet if you run a slip on, filter, removed snorkel and air lid. I used a 150 main and it runs so much faster then it did before. I clean my filter after every time at the track now instead of every ther time but it is worth it to me.