400ex Needs to go faster

[njk4o5]

Hey guys, im going to mod my 400ex.
All my friends have z400s and i need to smoke them. Right now my quads stock

i was thinking

yoshimura full pipe
k&N Filter
Jet Carb(maybe 450r carb if i can get one cheap)
sprocket for more top end
and i dont know what else.

The thing is, a $300pipe only gives a 2hp increase? what is that? can you even feel it? im used to snowmobiles and a 2hp increase is absolutely nothing.

[brian76708]

with that you will most likely only running right next to them in order to smoke them IMO you have to go internal. by putting a 11 to 1 piston and stg 1 cam with stock bore you will probably beet them. but i suggest having a pipe and filter with those mods.

leave yoshi to the suzuki where they belong get something else IMO, everything looks good but the sprocket for top end seems odd because thats not going to make you beat them unless its a long road

[Pipeless416]

yoshimura makes good exhaust systems. a pipe may only add like 2 PEAK hp, but the gains throughout the powerband are worth it. on top of the immediate gain, you are uncorking the engine and letting it really benefit from any future internal mods that increase air intake and exhaust output. if any of the z's are piped, you will most likely have to get into internal mods to beat them. my dad has a z400 with a full big gun evo x. the thing can move. i would stay with it until 5th where his just walked away. ive got a few things up my sleeve now though ;) . good list, so far.. add a 450r carb and a stage 2 hotcam with an 11:1 compression piston. you'll be set.

[Pipeless416]

ps- leave the gearing stock, or gear even lower. how often do you go 70 mph? i'd rather go 60 and get there a hell of a lot quicker. also, are you racing flat, straight lines? as many people say, suspension will make you faster than horsepower. a stock 400ex can already outpower its stock suspension limitations.

[jcs003]

Originally posted by Pipeless416
ps- leave the gearing stock, or gear even lower. how often do you go 70 mph? i'd rather go 60 and get there a hell of a lot quicker. also, are you racing flat, straight lines? as many people say, suspension will make you faster than horsepower. a stock 400ex can already outpower its stock suspension limitations.

thats a fact. unless your less than 160 pounds the stock suspension is useless, and even then its subpar.

Yeah I was surprised how quick a z400 was that has a full exhaust. If I had new tires i would pull a length or more but I had to give it credit for putting up a fight, bald tires suck BTW when you dont even have that much done but your spinning until you click 4th you know you need new ones.

[Ryan'07400ex]

Originally posted by jcs003
thats a fact. unless your less than 160 pounds the stock suspension is useless, and even then its subpar.

What if your 100? hehe
I wonder why Honda doesn't improve them?

[jcs003]

Originally posted by Ryan'07400ex
What if your 100? hehe
I wonder why Honda doesn't improve them?

then you must eat more.:D

[brothers]

i got an 400ex and i put an new full exhaust and chain and this moves. I am getting it jetted today and my timing key and rev box come in tomorrow i will tell you how it goes when i race my friends 450R on the track PS im a better driver.

[njk4o5]

well we race on a long staright paved street. So tires dont matter, and top speed does. I actually hit 70mph alot. Especially when the lake is frozen.

So im good with the yoshi pipe,

how many teeth should i go up on the gearing. The z400 is about 3mph faster from what ive seen. So 2 teeth should allow me to pass him right?

[atvmaster0927]

Originally posted by njk4o5
well we race on a long staright paved street. So tires dont matter, and top speed does. I actually hit 70mph alot. Especially when the lake is frozen.

So im good with the yoshi pipe,

how many teeth should i go up on the gearing. The z400 is about 3mph faster from what ive seen. So 2 teeth should allow me to pass him right?

IMO it's not worth getting a +2 sprocket for top end. It will take you a long time to reach top speed plus it will take a while to rev each gear out. stick with stock sprocket size.

[BEAVER.989]

Play with this to see what gearing changes will do for your top speed..

http://home.earthlink.net/~gellett/400ex.htm

[jcs003]

Originally posted by BEAVER.989
Play with this to see what gearing changes will do for your top speed..

http://home.earthlink.net/~gellett/400ex.htm

thats cool. thanks.

[njk4o5]

thats why i wanted to mod my motor, to make up for the lost acceleration by gearing
i want to make it pull just as hard, but go faster top end

[richards]

IMO you would spend less money and would be more satisfied if you just sell the 400ex and buy a 450R. The 450R was designed with top end power in mind and will excel in straight line speed contests.

You can spend a lot of money (and time) on pipe, cam, cylinder, piston, carb, etc for the 400ex and still be down on top end compared to the 450R. Plus you will be pushing the limits of the air cooled motor.

I love my 400ex because it has plenty of power for me and the low end is great for tough trails. That is what it is best at.

[brothers]

i agree with him...go race them on a track and if they win by a little then go practice. I know that you said you just raced in a straight line but thats not really what the 400ex was made for, I raced my buddies 450R and he had me by a bit but i will probably beat him on the track. In the words of Adrian "smooth is fast and fast is smooth" lol

[njk4o5]

i love my 400ex. its never failed to start. Most reliable quad i have ever owned.

And it wont sell. I cant even get 2000 for it. So then id need to save up $1000 for a 450r that doesnt have elec start and might not be as reliable. Im not getting rid of my 400ex. Love that quad. I want to make it go faster in a straight line on pavement. Thats the only way to see whcih quad is faster and thats where i will race every once and a while.

Lots of people have a 440 big bore. Is that hard to do?

[brothers]

440 is gonna cost a bit but i heard it was nice but not as reliable. I was looking into the 416 kit. since its only a piston and a few other parts(someone correct me if im wrong) and you get the power and reliability. have you looked into the 450R carb?

[Wheelie]

A 400ex can be built to hang with lightly modded 450's and still retain reliability. Both in a drag race and on top end.

[brian76708]

Originally posted by njk4o5
i love my 400ex. its never failed to start. Most reliable quad i have ever owned.

And it wont sell. I cant even get 2000 for it. So then id need to save up $1000 for a 450r that doesnt have elec start and might not be as reliable. Im not getting rid of my 400ex. Love that quad. I want to make it go faster in a straight line on pavement. Thats the only way to see whcih quad is faster and thats where i will race every once and a while.

Lots of people have a 440 big bore. Is that hard to do?

just to let u know to do a 440 kit right your going to spend around 1000 and could easily go over.

[jcs003]

a 400 can hang with a 450 in alot of areas, it may even be better in the woods. the issue is a 450 is more responsive to mods because of liquid cooling. keeping a 400ex at a good operating temp with mods can be difficult, and thats why bigger oil tanks and oil coolers are a must.

a good 460 or so kit will eat 450s all day until they start modding them then forget about it. but my built 435cc 400ex leaves my riding budies behind in the woods on their 450s.

but the winner in my opinion is always a 250r.

my 2 cents...

[Wheelie]

Mine is dead even with a friends 07er with full exhaust, filter--no lid, HC stg 2 and 12 tooth. Drag race and top end is dead even, in the sand running the same paddles--8 paddle Extremes.

[BossHogg420]

why are you so concerned on beating ur friends on a flat road race....if thats ur main concern get a street bike! not to get ur hopes down but to build an ex to run with ur friends quads your going to spend a lot more than the 1000 it would take to save up for a 450...if u really want to keep the quad set it up to beat them on the track or trail not the road....not trying to bust ur balls but adding teeth to the sprocket is only going to hurt u on the trails and track where it matters. and if u only ride on the road get a cbr1000rr and really smoke them :D

[njk4o5]

there are no tracks anywhere near my house at all. a flat straight road race is the only way to see whos is faster.

but yeah i think i found someone who wants to get rid of there 450 for my quad and some cash.

[krt400ex]

Originally posted by njk4o5
well we race on a long staright paved street. So tires dont matter, and top speed does. I actually hit 70mph alot. Especially when the lake is frozen.

So im good with the yoshi pipe,

how many teeth should i go up on the gearing. The z400 is about 3mph faster from what ive seen. So 2 teeth should allow me to pass him right?

if your only racing to see who has more top end then lengthen the gearing. if you want to beat him on accel, then shorten it.

[njk4o5]

we are only top out for a few seconds. and i will increase gearing. its a quarter mile race so its not all top speed that wins.

[bigbad400]

look at my mods..... i have a ex and a z400 in my garage, z400 has big gun pipe and k&n filter outerwears and ehs lid, nothing else but handlebars and some dress up stuff, my 400ex has got some into it but not alot as far as power adders, i can take it off the line about 4 foot ahead until 3rd then i just pull away, dry road dirt road sand dunes, hill climb and track my 400 out performes my z in speed and in handleing and in power, i have maybe 700 in power adders on my ex and i can beat a piped z400 easily they are not all there cracked up to be. id say a cdi and moster coil and a good pipe (yoshi is fine) open airbox with a good filter uni or K&N. and the sparks key. id bet money on it, the advantage is liquid cooling wich in turn makes it a faster reving motor, advance the timing and spark energy and remove the rev limiter, and our ex motors rev much faster now, open the exhaust up and the airflow up rejet and its good to go.

good luck on beating your friend, once you win he'll sell it and buy a honda!!!!

250r's are junk anything you gotta mix gas for is a waste of money, thers much more reliable cheaper and faster quads out there that you pore gas in and ride, forget 2 smokers, when you foul a plug on the trail or lock it up cuz your mix was off a little and all your buddies go roosting past you laughing on there 4 strokes maybe then you guys will believe me. ill beat anyone of them quadzillas and banshees alike, ride 2 miles an hour in front of them for 10 minuts till they foul a plug then cruise on.

dont get me wrong i love the power of a 2 stroke too but as far as trying to keep one in good operating condition ill take the bigger 4 strokes anyday. i hate rebuilding my quad once a year because i messed up my premix, or the thing got to hot and seized. i havent touched the inside of my 400 sice i got it. reliabilty means more than speed.

[njk4o5]

thanks dood thats just what ill do.

ur right, Z's arent that much faster. stock for stock, all they have is 2mph faster topend and a longer 2nd gear.

[jcs003]

Originally posted by bigbad400
look at my mods..... i have a ex and a z400 in my garage, z400 has big gun pipe and k&n filter outerwears and ehs lid, nothing else but handlebars and some dress up stuff, my 400ex has got some into it but not alot as far as power adders, i can take it off the line about 4 foot ahead until 3rd then i just pull away, dry road dirt road sand dunes, hill climb and track my 400 out performes my z in speed and in handleing and in power, i have maybe 700 in power adders on my ex and i can beat a piped z400 easily they are not all there cracked up to be. id say a cdi and moster coil and a good pipe (yoshi is fine) open airbox with a good filter uni or K&N. and the sparks key. id bet money on it, the advantage is liquid cooling wich in turn makes it a faster reving motor, advance the timing and spark energy and remove the rev limiter, and our ex motors rev much faster now, open the exhaust up and the airflow up rejet and its good to go.

good luck on beating your friend, once you win he'll sell it and buy a honda!!!!

250r's are junk anything you gotta mix gas for is a waste of money, thers much more reliable cheaper and faster quads out there that you pore gas in and ride, forget 2 smokers, when you foul a plug on the trail or lock it up cuz your mix was off a little and all your buddies go roosting past you laughing on there 4 strokes maybe then you guys will believe me. ill beat anyone of them quadzillas and banshees alike, ride 2 miles an hour in front of them for 10 minuts till they foul a plug then cruise on.

dont get me wrong i love the power of a 2 stroke too but as far as trying to keep one in good operating condition ill take the bigger 4 strokes anyday. i hate rebuilding my quad once a year because i messed up my premix, or the thing got to hot and seized. i havent touched the inside of my 400 sice i got it. reliabilty means more than speed.

250r's are junk????LOL. pouring a couple of oz. of oil in the gas is no big task. i rarely foul a plug and a rebuild is even rarer. 400ex's are great but since i got my 250r the EX sits.

[BossHogg420]

yea two strokes are the ****......miss my old rm125 had it for 7 years and put one plug in it.....still ripped the day i sold it...as far as premix goes.....only an idiot could mess up a ratio cup

[BD444]

I love the R for riding around the track and open trails, but anytime I need to speed the woods and goo through some ****...I take my ex.
I like the R more, but mine is absolutely mint and I want to keep it that way,
The ex is my sunday quad.:D

[RATPACK Z400]

Bigbad400, the z motor is an awesome motor you cant take that away from the Z, liquid cooling not the only thing making it faster its a dual overhead cam high performance motor theres guys getting 40hps with just carb/cams/port, on stock bore you not going to get that without bigbore/crank mods not to take anything away from ex it a great quad aswell just hasn,t got the high performance motor the Z has.As for the 250r the Z motor was the first to beat the 250r so thats got to say something about it.Your list does,t show motor work and your beating Zs bad HMM does z have stock tires? if it does thats a disadvantage switch to good tires you will see ex behind you next race.