Make an ex scream

[mred232]

Hi, i recently bought a 2003 400ex and i havent even put 10 hours on it yet and was wondering what performance parts to put on it to make it scream. I was thinking maybe yoshi or stage IV exhaust system and k&n jet kit, but i have heard that the filter passes fine dust and sand like at the dunes. I was also thinking razor tires. But any advice will help a lot.

[RiPPiNiTuP7]

I would get a LRD or Sparks Exhaust, a UNI Filter, and remove the airbox lid...you should have a smile on your face for a while from those mods :D

[mred232]

ok thanks for the advice im mostly ride in hard pack. What advantages will i get to removing the airbox lid? Well thanks for the advice.

[Crawl69]

I would go with a uni filter and a new silencer, I have a t-4 and I really like it. I think the stock tires are actually good enough to keep on there.

[mred232]

Well i wasnt going to change the tires till they are worn. But im sure the stock front tires will last a long time. Well i will look at the uni filters. I also heard that the stock 400ex throttle doesnt open all the way at WOT. I heard it only opens 75-85%. Well i will think it over after we take it in for the 10 hour checkup thing. Does putting performance parts on it void the warranty?

[oynot400]

First thing is to pick up the phone and call Mike at For Dirt Only. Tell him that you want a 463 or a 493 kits. Send him the motor and a check. In a short amount of time you will be one happy camper! :devil
On the cheaper side a good pipe, filter, and proper jetting will tame your power thurst (for now). :confused2

[CUZ'n]

i made my ex scream and the policeman came:mad:

[mred232]

I dont think i will go all out with boring it over to 463 or 493. I just want my ex to go fast. You know more bang for the buck. I also heard a 14 t sprocket increases acceleration. Thanks for all the help.

[oynot400]

I was just throwing that out there. :)
Yes a 14t front sprocket will help with accelation, but it will kill top speed. Just something to keep in mind. ;)

[forum]

if you have alot of money to spend buy a whole setup pipe silencer engine mods. blah blah. But if not. Don't waste your money on a headpipe. they do very little for the cost. slipons work great. If your on a tight budget get a slip on, remove airebox lid. get a K&N filter with jet kit. That will realy wake up your engine. after that get into the engine. flow the head, put in a cam, 11:1 compression piston with a 416 kit. and if you do this do it all at the same time. the less your pulling your engine aprt the better. but if you really wana go faster accross the ground get suspension! that will do the most.

[neals03400]

get a hetrick pipe and K@N power kit no lid. thats what i started with and has alot more power all oruond than stock. i dont think u need to over bore. i run faster than 416 and 440 with twice the money invested that i have. with stock bore 11:1 and s2 hot cam and ported head.as far as sprockets i would go up, your ex has enough bottem end.

[mred232]

Well Im saving all my money and i have around 250$ But hopefully i will get a job this summer for 10$ an hour. Then i will have some more money to put it in to it. I was thinking of getting a complete exhaust system. But i will consider the slip on. I will take the air box lid off and hopefully buy a k&n filter with outerware and jet kit. Then i think i will ride around for a while then do more major motor mods.

[mred232]

Thanks for all the help!!!:o

[jesshamner]

What do you people w/o airbox lids do when the riding conditions are sloppy or you go through a lot of water?

[sly400ex]

You are correct baout the throttle also. Pull back the rubber boot on the thumb throttle assembly and back the screw out until there is little or no play in the throttle. No airbox lid will let more air flow to the motor= more power! Get a 14T also. The topend loss is not bad at all for the bttom end gains! Also, until you start boring the motor or anything, don't bother with the header. There are some welds in it that you can grind down to let it flow better also. Just stick around at this site for a while and you will pick up some great info!;)

[Str8Wicked]

Originally posted by jesshamner
What do you people w/o airbox lids do when the riding conditions are sloppy or you go through a lot of water?

I go through streams and mud with my 400 with an open aluminum air box. Unless you are dunking your machine more than half way than the fenders will usually deflect the water and mud from the air box. I also run a K&N outerwears and also have an outerwears to cover the top of the box if I will be doing a lot of riding in water. I never have had a problem thou....

[nojoke4stroke]

Originally posted by jesshamner
What do you people w/o airbox lids do when the riding conditions are sloppy or you go through a lot of water?

ive ran mine for 2 years with a k&n,no outerwear and no airbox lid.ride in the slop just like i do everywhere else,WFO.when the filter gets caked with mud just clean it if youre not happy with the performance but it takes alot of crap on a k&n to notice anything significant.i dont understand why people are so scared of k&n's,make sure its oiled well after cleaning and then hit some dust while the oil is fresh.the immediate oily dust catches any fine particles you encounter in the future,this is how they are designed to work.as for mud and water,just run it.

[Crawl69]

a k&n rep told me to have a foam prefilter in dusty conditions

L&N suck in my opinion, i an one for a year, and it let in dust and water in my motor, i ran a race that had puddles in it, i couldnt even finish the first lap cuz my bike wouldnt run cuz it was sucking all teh water in, i run a UNI now and i am VERY satisfied with it, im selling my K&N for 35 plus shipping, ;et me know if you end up getting one

[WildCatRacer]

oynot400:
call FDO is right. I have a 250X that will kick the crap outta a lot of quads. heres FDOs info if anybody wants it:

For Dirt Only Racing
10275 Appleton Rd
Johnstown,OH 43031

ph: 740-967-1078

heres a pic of my quad:

www.geocities.com/quadrcr4/laegers

Originally posted by Flipper
oynot400:
call FDO is right. I have a 250X that will kick the crap outta a lot of quads. heres FDOs info if anybody wants it:

For Dirt Only Racing
10275 Appleton Rd
Johnstown,OH 43031

ph: 740-967-1078

heres a pic of my quad:

www.geocities.com/quadrcr4/laegers

rule #5

[AAAirbooorn]

first you tell her you want to get back together, after shemoves back in yiu tell her you were just kidding.:devil