building a high torque, lowend motor??

[400man]

is there any tricks to building a 400ex motor into a torquey lowend monster for mainly just trails and tight technical riding? I know that adding compression makes more torque, but at the same time loses some topend rpms if the cam is not changed to match, am I right? like for example, throw a high compression piston, like a 12:1 or bigger, in a close to stock bore cylinder and run a stock cam or stage 1 hotcam, stock header with slip-on pipe, would this combo have more lowend grunt and less topend pull then a stock powerband motor? and with a strong bottomend you can run a fairly high gearing and not worry about stalling as much at slower speeds, am I right?

[99RED4X4]

This is kinda the setup I was looking at. High torque all the way!

Your plans are probably a good way to go, although I doubt it will be the same top end as stock. You will probably gain lots of bottom along with some mid and some top.

If you make it breath better, it will gain power throughout no matter what. Now its also very easy to gain tons of top, and loose bottom.

For example, many people think its cool to throw a 3" dual exhaust on a relatively stock v8. Bigger is not always better. When you do this, you loose compression, therefor you loose tons of bottom end!

Sorry, not much help, just rambling. Anyways, I'm with you, I want torque. I'm gonna go 11.1 on stock or 416 bore (depending on how my cylinder looks), stage 2 cam, porting, and stainless valves. Not sure what it will be like but it should be worth the try

[Brauap]

J.E. 10.5:1 416 Big Bore Kit
Agressive Trail Port & Polish
Hotcams Stg. 1 Camshaft
Edelbrock Pumper Carburator
CRF450 Cam Chain
Uni Air Filter
13 or 14T front sprocket
White Bros. E-Series

This set-up would be exteremly reliable, be torqy as hell, and still run on pump gas no problem!

I love that exhaust because if you put 1 disk in, TONS of low torque, and is very quiet so you can seek up on wildlife in the woods OR throw all 12 in and it will be fast as hell, loud, and sounds great!!

[99RED4X4]

By chance did you get this done at Proquad Performance? Or did you do it yourself?

I live right in ellsworth

[rubbersdown]

high compression 13:1+
stage 1 cam
aftermarket exhaust
re-gear a tooth or 2

[togup]

Originally posted by 400man
is there any tricks to building a 400ex motor into a torquey lowend monster for mainly just trails and tight technical riding? I know that adding compression makes more torque, but at the same time loses some topend rpms if the cam is not changed to match, am I right? like for example, throw a high compression piston, like a 12:1 or bigger, in a close to stock bore cylinder and run a stock cam or stage 1 hotcam, stock header with slip-on pipe, would this combo have more lowend grunt and less topend pull then a stock powerband motor? and with a strong bottomend you can run a fairly high gearing and not worry about stalling as much at slower speeds, am I right?

I personaly am not a racer but if I was concerned about stalling in low speeds I would look into a heavier flywheel ,dont know if there is one but ask the racers here they may know,just thought it is a valid point.

[bherriman]

If you ask me your idea for a build would probably have plenty of tourqe, however, I have never heard of losing RPM when upping the compression. Not turning enough RPM is a sign of weak valve springs. If you really want a tourqe monster stay away from any kind of porting/polishing. Porting moves the power up in the rpm range which isn't what you want.

[supertrooper90]

my wife and I both have 400ex's mines a 99 and hers is an 05. Hers is a weisco 416 with a stage 2 cam and a stock headpipe and a slip on. Mine, I just finished the motor like 2 weeks ago, is a je 10.8 :1 piston no base gasket and a sparks x1 drop in cam. If you want a torquey motor stay away from the stage 2 hot cam. The sparks is well worth the xtra $50 it has a decomp mechanism, much quieter cause it uses stock valve specs, and the torque curve starts at the bottom and just keeps going!!! I had my head ported too and it still has lots of torque. needless to stay when i get a few extra bucks my wifes quad will be getting the sparks cam too. And if you wanted I dont see why you couldnt just leave the stock cam or do an xr400 cam.

[supertrooper90]

and with the stock cam, your not gonna loose any topend rpm's, you just wont get the added benefit mid range and up top as you would with an aftermarket cam

[Brauap]

Originally posted by 99RED4X4
By chance did you get this done at Proquad Performance? Or did you do it yourself?

I live right in ellsworth

Are you talkin' to meh? ARE YOU TALKIN' TO MEHH?
No, I didn't have it done either way, when I had my 400EX that was my dream set-up for racing HSs

And do you work there? Is it still on 224 past Fairway or did it move?

[CJM]

Idk guys, I did 416 11:1, dyno jet, open airbox with outwears and uni filter, stg 2 cam, stock sprockets on 20 kenda klaws and imho its plenty torquey for me. I find Im never going slow enough to really worry about the low rpm range.

[99RED4X4]

Brauap - Yea i was talking to you. Yea its still there, they just moved like right next to where they were at harv's cars. Their directly across from tip tools. I've BS'ed with the owner greg a few times, but no I don't work there.

CJM - see the set up I want is gonna be a tough one. Cause quite often I ride with old men (no offense to you troopers on here) on 4X4's who ride slow as dirt. I ride slow, I ride fast, I wanna be able to do it all.

[CJM]

Sparks cam might be the best choice of it all with an 11:1. Sparks cam iirc is about inbetween a stage 1 and stage 2 hotcam.

I just find with my combo that no matter the gear its plenty enough for me, stock vs mine its a no brainer, vs my friends stock with stage 1 cam is the same.

I think you might want the sparks cam b/c of the profile like I said is inbetween the 2 stages of hotcam.

sparks cam (http://www.alwaysopenmall.com/layouts/02/unsecure/item.asp?SiteID=223&DepartmentID=85&CategoryID=949&GroupID=7035&ItemID=31629&StartNum=1&Sort=&ShowPics=0&ListByCode=1&Brand=&GenderAgeGroupID=0&MaxPrice=&SearchString=&ItemCode=&IsOnlyOnSale=0&FromHomePage=0&FromFamily=0&ProductFamilyID=0&RelatedItemID=0)

[99RED4X4]

Someone said that the sparks come with the decompression unit...

I thinking that my dcomp unit is shot. Got a heavy tick in the top of the motor.

Do hotcams come with it

[CJM]

hot cams do not come or work with the decomp, they eliminate it and the ticking sound is the way the valves are adjusted.

Apparently you adjust them to the hotcam specs and run it to break it in for a while, then you can run it at the stock specs with no problems-thus no tapping.

[99400esex]

This is a really interesting thread seeing as how I want the same type of setup. Lots of good ideas

[99RED4X4]

No decompressor on a HotCam... hmm Is it hard to start???
I'm not saying I don't believe you, but why don't the talk about that in the company's product write up? I think alot of parts need more in depth descriptions... You know?

[CJM]

I have no issues starting it, turns over great. No idea why they dont use the decomp tho.

[smorris1]

I have a stage 2 hotcam and it has plenty of low end with an extremely strong midrange. I would totally recommend it. Match that with a 11:1 piston and your set.

[400man]

right now my EX has 14/36 gearing with 20in. razrs. motor is basically stock and across a long open field when I whind out the gears, it feels like it takes forever to whind out 4th and especially 5th. I never hit the rev limiter so I guess my rpms are around 5-6000 when it feels reved out? if you have a motor that makes the most power at that rpm range, then would it sorta have the same speed as a bike thats geared a little lower but making more topend power closer to the rev limit?

[ish416]

My setup is by far the torqiest 400 I have ever ridden. My friend on his uncorked Raptor 700 is jealous of the off idle torque my quad has.

12.5:1 416
XR400R cam
mild porting
40mm FCR
K&N no airbox lid
Fmf powerbomb / White bros E series slip on
stock gearing and 20 inch tires

I can easily pull the front end up at 25mph in 5th with just a stab of the throttle and tug of the bars. It will do the same thing at 55mph almost just as easily.

My friends and I commonly refer to it as the "tractor" or the "diesel" because of the torque.

As far as the powerband of the engine, there really isn't one. It's basically like a stock EX's midrange right off idle with that much more throughout the rpm range. Mine does fall a little flat once past 3/4 throttle completely because of the cam. However, the FCR carb really helps on the top end compared to the stock carb.

It is a great setup and I have been running the engine this way for several years (6+) without any issues. There have been a few changes such as the exhaust and carb but internal engine work has not changed.

It started out with the internal engine work and stock carb with just an fmf powercore 4 slip-on. Then I purchased a full WB E-series exhaust and it had better top end at the loss of the low end torque. Then I purchased a powerbomb header and ran my powercore 4. It gained a little bit all around. Then I decided to try the powerbomb header and a WB E-series slip on. I decided that it was the best exhaust I had ever ridden on my EX and have stuck to that. Then about 3 years ago, I switched to a 40mm FCR and have not looked back.

Everyone who rides it comes away impressed, especially those on raced out 450's and other big bore quads.

The only EX that I have ridden that has this type of power was a 440 stroker. It was running 12:1, fully ported head, custom ground cam supposedly between a stage 1 and 2 hotcam and an FCR. It seemed to have a very similar powerband as my quad except it revved out much quicker.

[bigbad400]

Originally posted by Brauap
J.E. 10.5:1 416 Big Bore Kit
Agressive Trail Port & Polish
Hotcams Stg. 1 Camshaft
Edelbrock Pumper Carburator
CRF450 Cam Chain
Uni Air Filter
13 or 14T front sprocket
White Bros. E-Series

This set-up would be exteremly reliable, be torqy as hell, and still run on pump gas no problem!

I love that exhaust because if you put 1 disk in, TONS of low torque, and is very quiet so you can seek up on wildlife in the woods OR throw all 12 in and it will be fast as hell, loud, and sounds great!!

i have heard nothing but bad noise about them edelbrock carbs, very unreliable, they say you have to contantly tinker with them. id get the 450r carb... best bang for the buck and very reliable.

[bigbad400]

the last one i built was 10.8:1 piston
stg2 hotcam
hmf pipe with fmf powerbomb
crf chain
450r carb
driven HD clutch(bites right now. love this clutch)
22 rears 23 fronts
13 t sprocket


i built it mainly to climb hills and trail ride... absolute beast off the line, pulles on stock 450s all day off the line. when i drag race i use 2nd or 3rd and i can jump about a length ahead of my ltr when it was stock. thats torque!

[whc]

I just finished building a 416 11.1 comp, stage one hot cam, new chain, air box opened up, stock ex. with a modified end cap, jetting is 168 main, one step bigger on low speed. this set up is noticable stronger on the bottom and pulls harder all the way to the rev limiter. I am very happy with this motor BUT I do have a problem with pinging when she gets hot, I am currently running about 105 octane fuel which has calmed the pinging quit a bit. Am also waiting for my larger oil tank to arrive, and am going to add a fan when I do my winter over haul. good luck Bill

[400man]

just thought i'd bring up this topic again........ im deffinatly planning on freshening up my motor this winter and im still reading about all the different options to go with. my head gasket is leaking right now and im gonna pull the head here eventually and decide if I want to bore the cylinder or not, its still on stock bore and if I can get away with it i'd like to keep it at 85mm, but if I have to bore Im gonna go to a 416. and for compression I think im gonna go with 12:1. gonna send the cylinder to GT Thunder and have em put the hd studs (and bore it if it needs). I have access to race fuel so its not much of an issue for me. my 250r I had a while back had to run on 110 race fuel so its not really much of a concern for me as far as the cost, plus the smell of it is just awesome :o . pretty sure im gonna go with a lowend cam like a stage 1 hotcam or something similar.

[tri5ron]

i've just read through this entire thread, and the one thing that no one has addressed is the style of riding you originally stated.
Trails, Tight, and Technical, usually imply much slower speeds as compared to racing, or open desert.

The thing to remember about going to a higher compression is that it DOES create a significant increase in heat.
Read--- Head temps, Oil temps,etc.
(and these are Air Cooled Engines).

I do MOST of my riding at a slower speed, in Technical trails, Washes, and Rocky hills.
This is all there is in the Deserts of So. Cal., and the weather is often 90 to 110 degrees.

(at 110 degrees, I'm back at the camper, A/C on high, and sucking down a cold beer !)

In responce to your original inquiry of trails, and tight technical,
I would highly suggest you keep your compression at 10.8 :1 or LOWER, simply because you are probably not going very fast,....
and therefore you often don't have a great amount of airflow to keep it cool.

For low end torque,
Stay with a stage 1 cam, or the previously suggested XR400, or Sparks X1 cam.
(of those 3 choices,.. I'd go with the Sparks X1)

A few other suggestions for you to consider would be,...
A larger oil tank, and/or larger oil cooler
A Spal fan mod on the oil cooler
A XR's Only oil temp dip stick
A Sparks +6 timing key
A '04-'05 450r carb properly jetted to your specific machine

And of course, if you want to make it into a Stump pulling, Arm Yanking, Trench Digging, Torque Monster,....
all you need to do is drop 1 tooth on the primary sprocket.

But the POINT of my reply here,
is to remind you that added HEAT,
and
LIMITED or Reduced airflow
is not good for our air cooled engines,...
and should be compensated for.
(or at LEAST closely monitored),
if you want to maintain the high level of reliability that the 400EX is known for.

(12:1 comp, and "Tight Technical", = Bad Choice ! )

(10.5 or 10.8:1, is fine, and, = less cost ,due to no need for the HD stud job, and no need to run expensive race fuel)

just my .02 cents

[honda400ex2003]

:D :D im in agreement with ron. stay lower comp, stage 1 or x1 cam. enjoy your happy face while riding. i may have to pick one of these x1s up to see how i like it. does anyone have a used one? steve

[CJM]

Yes, its not a good idea to go high comp if your going slower. Its the same reason I have a spal fan and will eventually upgrade to a larger oil tank at some point.

When riding I usually have my spal on when Im moving slowly and kick it off when Im moving for a decent bit of time. I have an 11:1 piston and stage II hot cam.

[whc]

good advice Ron, I may go back to a standard comp piston if the larger oil tank and fan dont cure my pinging. but I love the way my motor works for hare scrambles, I run in the fourty plus class, against mostly 450 race quads, and have been first or second at every race this past season, my quad just does not wear me out like my 450 does. where did you get the xr oil cooler dip stick did it help? thanks Bill

[yonsracing]

Who makes a bigger oil tank?

[tri5ron]

Originally posted by yonsracing
Who makes a bigger oil tank? Um

[honda460ex]

If you want an EXTREME torque monster... :cool: Go with a +2mm Stroker Crank and rod from Hot Rods. Get you a 13:1 compression piston, preferably JE, with a +2mm higher wrist pin location. Stick with a stage 2 Hot Rod cam. With the extra 2mm stroke, the compression, and that cam it makes an insane amount of low end. You will need it to breath very well and you will need race gas... But hey, every extreme has its price. I built that combo years ago and still have it today. Mine does have a ported head with 1mm larger intake valves, an old 42mm 450r carb, and GT thunder exhaust. The only change I made was I upgraded to the stroker cam from Hot Rods and dropped the Stage 2. I had no top end power. It would start dropping off around 6,000 rpm or just before and drop quick. I wanted my power to be more equal through out. But before I changed to the stroker cam it would lug up a fairly steep hill in 5th and just keep on lugging. Barely crack the throttle and you were up and cruising. I did upgrade to a 3 quart oil tank and have had no problems with it getting to hot, but I can't remember where I got it. Good Luck!

[MtnEX]

Lets not forget here guys that there is this big word call PERCEPTION involved here.

How people reference to torque and low end, ect... well that is a big part of things and you have to get on the same page about it...

I'll give a real good example...

When I say low end or torque, what I really mean is.... grunt down low, hard to stall at low speed/rpm, and will pull out of a bad situation a gear too high without having to slip the clutch.

On the other hand, when my buddy says low end, what he really means is.... throttle response off the bottom, crisp, snappy...




Now the mechanical reality is that the 400EX does not really make a lot of torque or HP.

What it does have though for the slow or tough going is a lot of grunt.... Pretty heavy internal moving parts.... it has a lot of flywheel inertia....

The old motor don't make any big numbers, but what it has going for it is the fact that once you get the crank turning, it is a LOT harder to stop!



When I bought mine it had 14/38 gearing and I have stuck with that. I feel like it could pull 15/38 OK, but don't know that to be true because I have not tried it.

But I can ride it all day with much ease when following 4x4's or much slower riders... and I can get it up some bad hills with ease, without having rev it to the moon, or nurse and baby it along riding the clutch to keep from stalling it out.

[honda400ex2003]

my next high torque engine will be the 440 11:1 wiseco with a stage 1, 450r carb, probably an fmf header, and my t4. I may run the stage 2 but im not sure yet. should be pretty cool. I may even add a bit of timing advance to see how it likes that. I was thinking 3 degrees with some 110 to really have some fun. i may even run a lightened fly wheel to help it spin up a bit quicker. ill see if i can get it cut some time soon and add it to the summer list. I think if i went with the lightened flywheel i would leave the stock key in and do a stage 2 in it to see how that works.

it should still have plenty of low end with great mid and top to go along with it.

ut ill see how much 110 is this summer and how much i want to spend on 55 gallon drums of it so i dont have to drive 75 miles to get 10 gallons or something. i know there is some closer too so i will have find out where it is. lol steve

[CJM]

See, I still think the 440 while being awesome just doesnt rev nearly as quick as say a 416 or 426 does.

If I were to do it all over I think I woulda done the 416 or 426, stage 1, 14/39 gearing, 450r carb, full exhaust and 3 degree key and run at least 100 if I could find some nearby.

I cant wait to see what kinda torque I get out of the 14/38 sprockets I just put on.

[honda400ex2003]

Im hoping the flywheel will help that alittle bit without sacrificing too much crawling ability. I plan to try to do around 10-12oz but if i cant find a scale ill just start cutting lol and see where i end up. I have a good idea of where i want to take it off and how much i want to take so it wont be bad. i just have to get time to get it cut. I have had it for a year now and still havent done it.

I may even try it out on my 416 before i tear it down. it would be a great addition to my setup now. I would even run the stage 1 again with it if i didnt already have the 440 sitting there waiting to get dropped in. it is going to be a crazy spring thats for sure. hopefully i get some time to finish it up before i start school again at the end of may. steve

[CJM]

Sounds like a plan, lightening the flywheel I hear does wonders.

You have a busy spring, 250r, 440 kit.. Me I just get to add a-arms, perhaps some new wheels, new front tires, buy a set of paddles, new steering stem, maybe an extended swinger..oh and most fun part-try and remove the swingarm bolt..

[honda400ex2003]

lol my fun has come to a halt for the winter now. lol i dont have any more $$ to spend so i guess i have to wait till spring to get the rest finished up.

I am yet to attempt my swinger bolt, i have bearings i want to put in it. they are getting worse so i guess it will be time to do it this spring. i have the new nut and bolt already too so i dont care if i destroy the one that is in there.

sounds like you have been having some fun also :devil: Gotta love AADS man. it can only be contained for so long before it comes back to bite again. lol steve

[CJM]

Yea, Im outta cash to a certain degree. Still jobless but I want to ride since I finally found a real spot to go, even if its freezing its soooo worth it.

So gotta fix what needs to be fixed. The old chain was BAD I mean took it off and it kinked with ease and its the original chain and its a 2000!

My swingarm bolt seems ok but like I said I dread removing it. At that point Im willing to bet Im gonna cut it out cause it wont come out and Im gonna wind up destroying swingarm-at which point Im probably gonna do an extended one.

Steering stem is EFFED, its twisted at the top and worst off it had 3 rides on it when I did it. I might buy a stocker since Its cheap and I know its gonna bend again and not destory something more important-but a nice shiny one is cooler right?

AADS is right.. Soon it will be done, then I can buy a 250R or a banshee and have some fun.

[rubbersdown]

Originally posted by honda400ex2003
my next high torque engine will be the 440 11:1 wiseco with a stage 1, 450r carb, probably an fmf header, and my t4. I may run the stage 2 but im not sure yet. should be pretty cool. I may even add a bit of timing advance to see how it likes that. I was thinking 3 degrees with some 110 to really have some fun. i may even run a lightened fly wheel to help it spin up a bit quicker. ill see if i can get it cut some time soon and add it to the summer list. I think if i went with the lightened flywheel i would leave the stock key in and do a stage 2 in it to see how that works.

it should still have plenty of low end with great mid and top to go along with it.

ut ill see how much 110 is this summer and how much i want to spend on 55 gallon drums of it so i dont have to drive 75 miles to get 10 gallons or something. i know there is some closer too so i will have find out where it is. lol steve

Steve if your going to run 110 anyway why dont you go 12.5:1? Compression makes a big difference and if your going to spend the money on the fuel anyway might as well get the free extra power.

and I gotta ask, what the hell is AADS? I have seen that on this forum a couple times and not quite sure what it means lol

[CJM]

The Disease is called A.A.D.S., which stands for :
Accessory Acquisition Disorder Syndrome

Hi, I'm Marc and I have AADS.

[honda400ex2003]

cause i probably wont be running 110 lol. i will have everything all set to run a 12.5:1 too since i will be getting hd studs for it too.

those were just ideas. I can get 91 octane within a couple of miles. I would have to go at least 20 minutes each way to get 110. not that it would be a big deal since i would just buy enough to last for a while but it is quite a bit more expensive than the 91 octane lol. steve

[CJM]

Funny thing is with my mods now it EATS gas. 110 even a 55 gallon drum wouldnt last to long at all. Could be the cold weather, could just be me beating on it.

In a 6-8 hour period Im usually out of gas and on reserve. This is all fast paced trail and dune riding too tho.

You might have the same problem steve, isnt 110 like 10/gallon?

[rubbersdown]

HAHA, Ive had AADS for like a decade now and I didnt even know it! hope I didnt give it to my wife, I told her I was clean!

Oh yah that would suck to have to drive that far to get fuel, ive been itching to build something fast recently too lol, I keep scowering the CL adds looking for a project.

[CJM]

I have had AADS for years myself, almost everything I buy I modify lol.

I shoulda bought this 400ex I saw on CL like 6 months back. Guy wanted 900 bucks and said it didnt run right. For that price I coulda talked him down to 6 or 7 and probably got it running and kept it or flipped it.

[rubbersdown]

yah I got my wifes current 400ex for 600 with a blown bottom end but the guy had already bought a new crank for it and just dint know how to put it together so the motor was split and in peices when I got it. I got 1100 into now with a brand new motor and tires and everything, im guna start a new thread on it once its 100% done next week. it was a fun little project. this forum helped alot sense ive rebuilt like 3 other 400ex motors for friends but never actually worked on the chassis or put the motor in the frame and what not. This place has been a blessing.

[CJM]

I seriously love this forum, most helpful atv forum ive ever seen.

Im a mechanic and had limited experience working on stuff like this and by now Im not half bad at it. Really paid off reading the info here.