400EX, can it go fast?

[Thump_It]

I've got a buddy who just bought a 2000 400EX, it has a WB E-series system with K&N. Also has a Hinson clutch. He wants to get as much power as he can out of the motor without sacraficing dependability. What kit will help him out the most. Money is not a problem. Thanks for everyone's help.

[kruzofman]

well dude there are lot's of company's out there with the 440 kit witch will give you lot's of power and has good realibilty, try

[kruzofman]

well dude there are lot's of company's out there with the 440 kit witch will give you lot's of power and has good realibilty, try CT RACING, DUNCAN RACING, TRINITY, those are some good companys to start with. good luck:)

[kruzofman]

dam dam fuuuu k sorry about the double post:o

[ridesa02400EX]

get a duncan racing national 440 kit

[jb500ex]

or you can buy my 500ex it's all done

[RED121572]

The most dependability out of the motor?...uh....leave the motor alone then. ;)

[R3Concepts]

If you want it to go fast and be reliable build a 426, my 426 will pull any 440 all day long. It takes a good builder aka Sparks to build a 440 thats worth keeping, but for that motor you have to cough up at least 3 grand.

[RED121572]

It doesnt take a special engine builder to put a good 440 together. Why on earth would you tell him that?

[yellowrider]

i would go with a 406 kit with a drop in cam (i think webcam not for sure)
then i would get a advance key from sparks racing for like 15.00
then i would buy a lrd pipe


the reason i said this is becasue a 406 you can go higher on the compression and rev a whole lot quicker.. even if you did miss something up you still have more room to bore



i raced a bad 416 and beat it by 3-4 quad lengths i raced a 406

with that above and we were dead even till 5th gear.. i just cant remember his cam !!! sorry !

i think it was web cam but i know for sure it was hotcams..

[R3Concepts]

I said that becuase its real easy to screw up a 440, and its pretty hard to screw something up with a stock sleeve still in it. Ok build a 440, this is America do what you want, but Im going to tell you that you will blow head gaskets, it will run hotter then a air cooled bike should, you will pull out studs. I can build a ex motor with my eyes closed. ANYONE can put one together, but not everyone can machine to exact tolerances that say a Sparks can. The local machince shop has more then likely not built a lot of 440 motors.

[Chef]

So you're saying that 1mm of piston size is the difference? Because thats what the difference is- 1mm. 88mm vs 89mm. (89.5 is actually closer to a true 440-89 is only 435.)

[R3Concepts]

88mm(426) is as big as you can go without re-sleeving the cylinder. When you bore out a sleeve, then bore for the new sleeve aka 440 sleeve, theres way to many places a machinist can screw it up. Most Ive seen or worked on, the machinist counter bores the top of the cylinder too deep, and the lip of the sleeve isnt pressed all the way down, so when it gets hot, it sinks, it sinks, the head gasket blows. If your going to build a 440 then the sleeve must be pressed all the way down, and the top of the cylinder needs to be surfaced(decked) down to the sleeve height. Hold a straight egde on all the surfaces, and hold it up to the light, if you can see light under the straight edge then its going to blow head gaskets from say one. So build a 416(87mm) or a 426(88mm) have it be reliable and pull 440s all day long.

[outofsight]

Does the 426 generate alot of heat?

[R3Concepts]

Ive never had a heat problem with my 426 but its got a lot done to it to get the heat out.

[stupid driver]

Originally posted by R3Concepts426ex
If you want it to go fast and be reliable build a 426, my 426 will pull any 440 all day long. It takes a good builder aka Sparks to build a 440 thats worth keeping, but for that motor you have to cough up at least 3 grand.

im with this one. My TC 425 is a monster. I finally got to race the new yfz about a month ago, and my 425 took it easily. They were pretty close off the start, but after i clicked into 4th, it was over.

[R3Concepts]

Amen brother, some just dont get it, bigger isnt always better.

[mascman]

Who makes a good 416/426 piston, and what cam would you match to it? This would be a woods motor...not MX.

I am trying to help my brother out and maybe get him the parts. After riding my 450R, the 400 seems pretty weak...I feel bad that he can't get a new quad at the moment.

If the YZF is supposedly faster than my TRX, it seems pretty amazing that a 426 could beat it. The EXs just seem slow-revving compared to the 450s. I'm sure his Ex could use freshening up anyways.

[cals400ex]

Originally posted by stupid driver
im with this one. My TC 425 is a monster. I finally got to race the new yfz about a month ago, and my 425 took it easily. They were pretty close off the start, but after i clicked into 4th, it was over.



what all do you have done to the motor? i know the 425 @ 11:1, but that is all i know you have.

what cam you running?

[stupid driver]

it has the TC mx cam in it. I can never remember if that is the 924 or 926 cam, its one of those two

[RED121572]

Originally posted by stupid driver
im with this one. My TC 425 is a monster. I finally got to race the new yfz about a month ago, and my 425 took it easily. They were pretty close off the start, but after i clicked into 4th, it was over.

Did you out accelerate it or out run it...or both?

[stupid driver]

I out accelerated it. I got into 4th gear on the strip we were on. It was close right off of the bat, but once i got to 3rd i pulled away. The yfz's are pretty wicked on the top, I wouldnt have bet money on my quad once he got into 5th.

[04'400ex'er]

Originally posted by stupid driver
I out accelerated it. I got into 4th gear on the strip we were on. It was close right off of the bat, but once i got to 3rd i pulled away. The yfz's are pretty wicked on the top, I wouldnt have bet money on my quad once he got into 5th.

Was it a stock bike? I believe the out accelerating part but on top it would be close i bet.

Originally posted by 04'400ex'er
Was it a stock bike? I believe the out accelerating part but on top it would be close i bet.

i dragged the yfz and the 450r in sand...a stock yfz and my bike run even then i begin to pull away...a piped yfz takes me off the line by about 3 bike lengths then i start to catch up but not enough to beat it in a 300ft...the 450r runs exactly the same as the yfz in the drags vs my bike...i beat 1 piped yfz and 0 piped 450r...there werent that many piped 450r down there dragging...but i beat 3 stock yfz and 2 stock 450r...they have mad accell vs my bike in the sand but i catch them in the long run...if i dropped a sprocket i bet it wouldnt even be close:macho :devil:

[Ryan]

Originally posted by stupid driver
im with this one. My TC 425 is a monster. I finally got to race the new yfz about a month ago, and my 425 took it easily. They were pretty close off the start, but after i clicked into 4th, it was over.


Do you have to run any mixture of fuel (race gas) with the 11-1 compression on yours?

[cals400ex]

Originally posted by XxHonda_RacerxX
i dragged the yfz and the 450r in sand...a stock yfz and my bike run even then i begin to pull away...a piped yfz takes me off the line by about 3 bike lengths then i start to catch up but not enough to beat it in a 300ft...the 450r runs exactly the same as the yfz in the drags vs my bike...i beat 1 piped yfz and 0 piped 450r...there werent that many piped 450r down there dragging...but i beat 3 stock yfz and 2 stock 450r...they have mad accell vs my bike in the sand but i catch them in the long run...if i dropped a sprocket i bet it wouldnt even be close:macho :devil:


what all does your bike consist of?
i believe a 11:1 416 with thinner gaskets, ceramic x-6, fcr 39, stage 2??

what gearing you running? are you running pump fuel? and head work?

Originally posted by cals400ex
what all does your bike consist of?
i believe a 11:1 416 with thinner gaskets, ceramic x-6, fcr 39, stage 2??

what gearing you running? are you running pump fuel? and head work?

im running 11.6:1 416 thinner gaskets, ceramic x6, fcr 39, stage 2 hotcam, stock gearing, race gas (i run race gas at the dunes, pump at home), porting polishing, and a few other things:devil: :macho

[R3Concepts]

A 416 will pull a yfz off the line, but WILL NOT pull a yfz on top end. Its not happening. My 426 will not pull a piped yfz past 4th gear. The yfz revs out so much higher then a EX motor. If you race a yfz with a pipe, filter, no lid, and the cam mod, a 416 will get off the line better, but will get smoked on top end.

[keepitpinned]

how does it compare to banshees and raptors?

[outofsight]

the yfz 450 will take the raptor and the banshee. R3concepts, do you have a rev box on your 426?

[R3Concepts]

My 426 has everything done you can do to it. My bike will pull a yfz off the line easy cause I run 14/40 gearing, but no 416 or 426 is going to pull a yfz on top end.

Originally posted by R3Concepts426ex
My 426 has everything done you can do to it. My bike will pull a yfz off the line easy cause I run 14/40 gearing, but no 416 or 426 is going to pull a yfz on top end.

mine did...mine caught up to them...i run different gearing

[R3Concepts]

I dont care what gearing you run 15/38, 16/36, 15/36, a 416 will not outrun a yfz450 on top speed, just wont happen. If there were 2 riders of the same caliber the yfz would win. Sorry.

Originally posted by R3Concepts426ex
I dont care what gearing you run 15/38, 16/36, 15/36, a 416 will not outrun a yfz450 on top speed, just wont happen. If there were 2 riders of the same caliber the yfz would win. Sorry.

ok whatever u say buddy...i was on the bike...my dad saw it...and my 2 dads friends saw it...and my dads friends wife saw it...u can ask ne of them...its the truth rether u want to admit it or not

[R3Concepts]

HAHA, was the person riding the yfz a 7 year old girl? Dont get huffy. Did she stall the bike? Was she pushing it?

[Chef]

Originally posted by R3Concepts426ex
I dont care what gearing you run 15/38, 16/36, 15/36, a 416 will not outrun a yfz450 on top speed, just wont happen. If there were 2 riders of the same caliber the yfz would win. Sorry.

I dont see why you think all 416's are created equal here...This isn't the only 416 I have heard of out running a YFZ everywhere. I have both ridden one and done it myself, and seen it done with my friend on his own bike.

[R3Concepts]

I didnt say that all 416s were equal or even close. All these times that the yfzs get beat by 416s there are 2 equal riders right? Doubt it. I race with a friend that has a yfz with a x6 exhaust, filter, no lid, and the cam mod and I holeshot him every race when I run a 14/40, but with my 426 with 15/36 I cant hold a candle to his yfz in a long drag race. He beats me by like 8-10 bike lenghts, so thats why I find it kind of hard to believe a 416 outrunning a yfz on top end, but maybe these are bone stock yfzs that you guys are racing.

Originally posted by R3Concepts426ex
I didnt say that all 416s were equal or even close. All these times that the yfzs get beat by 416s there are 2 equal riders right? Doubt it. I race with a friend that has a yfz with a x6 exhaust, filter, no lid, and the cam mod and I holeshot him every race when I run a 14/40, but with my 426 with 15/36 I cant hold a candle to his yfz in a long drag race. He beats me by like 8-10 bike lenghts, so thats why I find it kind of hard to believe a 416 outrunning a yfz on top end, but maybe these are bone stock yfzs that you guys are racing.

the bone stock 1 i can beat most of the time...the piped ones are the ones that smoke me to !$#@ then i begin to catch them on the long end...but i dunno if they had no lid or the cam mod...they jus had pipes as far as i kno

[stupid driver]

Originally posted by Ryan
Do you have to run any mixture of fuel (race gas) with the 11-1 compression on yours?

ya, i usually run 114 leaded 4/1.5 in the winter and 4/1 in the summer