more power for my 400ex!!!

[RobCradles]

hello, i'm new to motor sports (started may of 2005)... my friend told me to get a 400ex, he had no idea that i would become atv obsessed or he would have told me to get the 450r...
anyway, it has been over a year and i am now looking for more POWER!!!
what do you suggest???
i ride, most of the time, on my friends land that we are slowly turning into a mx / cross-country track (from time to time we rent a dozer to build more jumps)... i will race a few times a year but it is just for fun, i realize that if i really want to kick *** i need a 450r...
i have done many upgrades to my 2005 400ex:
Custom Axis Shocks (front and back)
Race A-Arms
Swing Arm
Axle
Stabilizer
Steering Stem
T2 Bars
Air Box
K&N Air filter
Race Peg Nerf Bars
Kill Switch
Case Saver...
i now feel it is time for more power but i don't want to work on my quad all the time, i like the reliability of the 400ex motor...
i was thinking a 416 high compression piston just to give me that little extra to keep up with the 450r's??? but will that require new springs??? will i have to work on the motor more with the 416 or a 440???
what do you suggest??? i DON'T have a bunch of $$$...
sorry for such a long post but i wanted to give as many details as possible so that you can give me a specific answer...
thank you -rc

[ktyfz]

I'd say go with the 416 over the 440. Khen is the EX expert, so if your lucky he'll chime in :-). My wife rides a fully modded 440 and it's a runner, but Khen's 406 seems to be faster, so I don't think that CCs is the key on the EX. Here's my suggestion.

416 kit with high comp piston
450R carb
Port & Polish
Sparks full system exhaust
Aftermarket CDI

You will probable need heavy duty valve springs and clutch springs, but you might get away with running the stockers.

[AKColby]

400ex = 450R


impossible

[Kev_CR]

Originally Posted by ktyfz

416 kit with high comp piston
450R carb
Port & Polish
Sparks full system exhaust
Aftermarket CDI

+ Hotcam (stage 1 for bottom-mid power, stage 2 for mid-top)

For reliability, install some heavy duty head studs. If you go 11:1 compression or higher you will have to run at least a race/premium gas mix.

This build will really wake up the EX!

[atvracer311]

before i built my hybrid i have a 416 10:1 kit with a stage2 cam, port and polished head,450r carb,k&n filter with no air box lid,full big gun exhaust
my bike could smoke most light modded 450's also it was geared 16/38 help alot..

p.s. if u do this i would run a 2002 crf450 timing chain.... fits great, it stronger and cheaper that stock

[crdemon]

Originally Posted by AKColby

400ex = 450R


impossible

Not true. I've rode one that would blow a mostly stock 450 outa the water.
But by the time you have that much into you might as well have bought a couple 450's lol

[TRXman86]

i agree with "demon". there are 400's with some work that will rip up a 450. i know cause at this years local 6 hour, i was on a bud's 440 and walked all over most of the '50's. easily. now this also goes to say what kind of rider you are. you can take a 300ex with a pro rider against a rookie on a 450, more then likely the pro will still win. depends on the rider.

as far as motor work, like khen said, if you like to go WFO, stage 2 hot cam, crf cam chain is also a good idea. if you buy an aftermarket chain, it will cost more then a stock crf chain, i am sure there is a review of what pipe will give you more power on here somewhere. if not, i will look for one somewhere. 450 carb will be fine, but if you cant afford one, try to send it in and have it rebuilt- main, pilot, needle valves, etc. etc...) high comp piston, (heavy duty head studs are a MUST!!! the heat from high comp, will expand the head and stretch the threads out bad. (know from experinace )

your off to a good start with the K&N, for a little less money and a little more juice, wait for the motor work, get a full exaust, re-jet, and get a stock bore high comp piston with the heavy duty studs. you will need to have the holes tapped out to allow for bigger studs to. get a nice set of gaskets also. dont want them to leak.

dang, almost forgot,

WELCOME TO THE FAMILY!!! please come back and shoot the breeze with us. take a look at the store also, you may find all you need. if not, shoot Woody YFZ a pm...think this is the right woody? i get 'em mixed up alot... DONT LAUGH

[cr250scott]

I didn't see any info about an aftermarket pipe. Is your pipe stock? My friends 400ex is much faster than mine and the only difference between the two of ours is his has an FMF power core and properly jetted.

[Ride.221]

Dude...my bike has an FMF powercore header, K&N air filter, its jetted, has a White Bros. slip on, and a HotCam---and I'm set. The thing flies. Fancy handlebars arent going to increase your cc's unfortunately. My bike has over $2500 in high performance parts--and he flies. My best advice is to stick with FMF and White Bros contraband. More power...more money, yes, but it will be cheaper than buying a new 450r lol. Good luck...

H3LiX

[crdude]

congrats, you just brought a two year old thread back to life.

[Ride.221]

LOLOLOLOLOLOLOLOLOLOLOLOLOLOLOL

[motocrossman7]

[B]dude he said he doesnt have a lot of $$$$

[Oklahomarider]

Im not trying to start a 2 wheel 4wheel fight but why do all 4 wheeler riders use a K & N air filter but anyone who owns a modern 4 stroke motorcycle and is half way serious about maintainance wouldnt be cought dead with a K & N on there bike?

[Kev_CR]

Originally Posted by Oklahomarider

Im not trying to start a 2 wheel 4wheel fight but why do all 4 wheeler riders use a K & N air filter but anyone who owns a modern 4 stroke motorcycle and is half way serious about maintainance wouldnt be cought dead with a K & N on there bike?

If you ride the dunes a K&N filter with an outerwear will filter out sand much better than a foam filter on all the quads I've owned. But, I haven't had a problem with foam filters in the sand on my motorcycle. The bigger tires and locale of the filter on a quad must kick up a lot more sand/dirt on a quad. I wouldn't run a foam filter on a quad ever again, I've rebuilt to many engines because of them.

[Oklahomarider]

Do you oil the outerware on the K&N? How often do you change foam filters. Are you oiling them, are you saying a K&N is better than a good oiled foam filter?

[Kev_CR]

Originally Posted by Oklahomarider

Do you oil the outerware on the K&N? How often do you change foam filters. Are you oiling them, are you saying a K&N is better than a good oiled foam filter?

Definitly do not oil the Outerwear on the K&N filter, It'll clog up in no time! I clean & oil my foam filters and K&N's after every ride. My experience with the foam filters on quads in the sand is that the sand sticks to the oily filter and eventully cuts/finds it's it way through.

With the Outerwear (un-oiled) the sand reflects off of it so it doesn't ever get to the filter and the oiled K&N does a good job with the finer stuff that passes through the Outerwear. In a fine dusty situation I prefer the foam, but in the sand without a doubt the K&N/Outerwear is a MUCH better solution in my experience.

Keep in mind also that I don't run an airbox on one of my quads (ESR kit) and the other has an open airbox.

BTW, I've tried about every foam oil made and have had the same experience in the sand. The UNI foam filters were the worst.

[Oklahomarider]

Thanks.

[swampgrass]

send it to the folks at Rage ATV they will make it go fast for about 12 to 15 hundred

[trx440r]

i have a 440 with 12.5 weisco stage 3 hotcam hd timing chain head milled kibble white valves stock pipe but i have cut it in half stock carb with only a 155 main jet no air box and i have never been beat by no other 450 or 400 of any kind

---------- Post added at 02:30 AM ---------- Previous post was at 02:26 AM ----------

well rc my 2005 head springs are stock. i have the 440 kit and i havn had no problems.