racing question

[trx400exrider14]

what all can i do with my 400ex to have it keep up with 450s in harescrambles without boring it out

[CJM]

Sparks timing key, exhaust, 11:1 or 12:1 piston, port and polish, stage 1 hotcam, good tires, good suspension (450r front shocks, have the rear shock revalved and resprung for your weight). Bout all you can do..

Will you keep up with the 450s,possibly, but a bigger bore will help greatly and at the point you do all I listed above its only maybe 100 bucks more to bore it out.

[supertrooper90]

there is really nothing you can do without getting into some cylinder work. All the bolt on stuff will wake it up quite a bit but not make it hang with a 450. If you wanna spend some $ do and 11:1 piston with a stage 2 cam a full exhaust and some port and polish work thatll get you kinda where you wanna be

If your doing harescrambles you could do the 450 shock revalves, gt thunder xc link, good 6 ply tires, skids, bumper and nerfs would be nice. Then motor wise- sparks timing key, exhaust, uni or k&n filter( i run uni and am very happy with it), rev box. Ive seen people run stock 400s and be competitive in say the 16-21 C class. Its about the rider, how far and how long you can make it and SUSPENSION SUSPENSION SUSPENSION! in harescrambles

[supertrooper90]

Ive run a few harescrambles on my stock bore 400 and suspension is the best place to start I did the gt thunder revalves and xc link I felt I could ride much faster and longer since my stock shocks werent beating me up

Originally posted by supertrooper90
Ive run a few harescrambles on my stock bore 400 and suspension is the best place to start I did the gt thunder revalves and xc link I felt I could ride much faster and longer since my stock shocks werent beating me up
The order i would go about doin this is: skids and 6 ply tires first, then Suspension a GT thunder XC link and 450r front revalves for your weight and just get the rear stocker revavled and resprung for your weight. Third i would get a pipe( i have a sparks on my 300 and love it, but theres not that much bottom end gained) and a uni or K&N filter(reccommend UNI). And if you havent done it before get some good nerf, heel guards, and peg combo, a nice bumper. I would maybe get a sparks key but i wouldnt do anything like boring to a 440 maybe a 416, 11:1 piston, cams, etc. Oh yeah and you need a tether kill switch to race.

[trx400exrider14]

i want to use 87 gas though

[trailrider894]

Originally posted by trx400exrider14
i want to use 87 gas though

Well i don' even run low grade/low octane in my quad and it is stock bore. I would suggest to keep the cylinder the same and not bore it out or change the compression ratio. Even an 11:1 requires the highest pump gas available to you. Having a hard time remembering what the highest is they sell here in my town. I am thinking 87,89,93 is what we have at the pumps. but in illinois i think i have seen close to 100 before.

[trx400exrider14]

yea,what is the highest compression i can go without using 93?

[Red_250EX_Rider]

Originally posted by trx400exrider14
yea,what is the highest compression i can go without using 93?

Im pretty sure that is 10:1 which is stock right?

[TCracin440ex]

i wouldnt run nothing no lower then 93 even on a stock motor or compression. 87 causes bad predet and pinging.

[slightlybent47]

Well you did say you wanted to hang with the 450’s. So quit finding excuses. You’re going to have to do something to accomplish that right? 11.1 is fine to be running on 93 and you’ll need more then just that to keep up with a 450. You’re never going to stay with a 450 on 87 pump gas no mater what else you do to it.
Depending on what type of racing you are doing has a big deal to do with how you build the bike and how it will perform against a 450.
Can you give a little more detail on what type of riding you plan to do?
Do you want your torque on the low rpm or the high rpm?
The 450 stock is what 47 hp? And a stock ex is 27. So a built ex pushes 50 hp tops when fully built. Now if the 450 is built then were talking 65 hp.
Now if rider skill is equal then the only deference is useable power, how much of that power can you use and stay in control?
See where I’m going here?
Also a 450 is water cooled and the ex is air cooled so the 450 is going to keep its hp longer if you ride in high temps. Even at low temps the ex hp will fall off do to heat. And the more its built the more heat there will be.

[slightlybent47]

After making the last post I got to thinking?
We all are trying to stay with a 450 or beat one, so what if you took an ex and put a 450 motor in it and could make the weight the same so everything would be equal except for the power of the motor. How well it would run against a built ex?

[CJM]

I agree with bent, either do the work to the EX to keep up with the 450 or buy a 450 motor/quad.

You gotta pay to play man, racing is not cheap.

I wouldnt put 87 in a stock motor much less in one with 11:1 piston. 93 is not that much more, maybe $0.50 on the gallon? Running 93 octane is alot cheaper then having your motor blow up because its running too lean

[trx400exrider14]

i think so,i worded that wrong,what is the highest using no higher than 93?

[Quadracer667]

i have a 400ex that is bored out 20 over 11:1 compresion with a stge 1 hot cam a full procuircut exhuast and a uni filter with a 158 jet and the 450's pull me a little on the bottom but it runs great for a harescramble and i run 93. keep in mind the higher compresion the more heat you have which causes prblems in a long race. but like everyone else has said suspension is key. practice and jogging to keep ur self in shape

[CJM]

Originally posted by trx400exrider14
i think so,i worded that wrong,what is the highest using no higher than 93?
11:1 for most, sometimes you can get away with 12:1.

[2001400exrida]

yeah for most, my 11:1 doesn't like 93. It was running so bad one day it was mis-firing.

i use the 110/89 mix which puts me right around 100 octane and it runs perfect!

[ish416]

11:1 for most, sometimes you can get away with 12:1.

I would hate to see what would happen if someone ran 12:1 on 93 octane in a 400EX. Simple answer would be a toasted top end.

For 11:1 you are pushing it on 93.

General rule is 11:1 is max compression for an air cooled engine and 12.5:1 for liquid cooled engines running 93 octane. Also, depends a lot on timing and other things. Hence why it is a general rule.

I have ran my 12.5:1 EX on E85 or 100LL and have had no issues over several years. On hot days I can't even mix pump fuel with E85 or 100LL without pinging issues.

[2001400exrida]

i agree with your post ish.

you have to figure if honda suggest 92 octane on a 9:1 stock compression motor,
Then, if you go up to 11:1 you're gonna want more than 93, say or think what you will folks, but i want my motor to last!

I'm gonna run nothing less than 100 octane on my 11:1, as i said before the 93 doesn't run good in it.

[99400esex]

Numerous people on here have said they run 93 on that compression with no ill effects.

[trailrider894]

Originally posted by 99400esex
Numerous people on here have said they run 93 on that compression with no ill effects.

ignore his comment. Nobody is getting anywhere by being a bunch of smart@$$'s while arguing.

[CJM]

Jetting plays a huge role in what gas octane you can run fine. my buddy has a 13:5:1 or something or other piston in his 450r, full exhaust and a cam and runs 93 no issues-but he is the king of proper carb jetting imho, he can get it spot on with no issues usually.

[99400esex]

Originally posted by trailrider894
ignore his comment. Nobody is getting anywhere by being a bunch of smart@$$'s while arguing.

I'm not being smart man. I'm just simply stating fact, I'm also curious as to why he is saying that because I plan on going to that compression and that high of octane rating doesn't exist around my area.

[trailrider894]

Originally posted by 99400esex
I'm not being smart man. I'm just simply stating fact, I'm also curious as to why he is saying that because I plan on going to that compression and that high of octane rating doesn't exist around my area.

I understand. I just choose to ignore people like that. I personally see no problem in running 93 in your 11:1 as long as you don't have a sparks key or advanced timing. I would just go ahead and do 11:1 and buy the best pump gas your town offers.

[99400esex]

Originally posted by trailrider894
I understand. I just choose to ignore people like that. I personally see no problem in running 93 in your 11:1 as long as you don't have a sparks key or advanced timing. I would just go ahead and do 11:1 and buy the best pump gas your town offers.

Ok thanks man. I meant no disrespect towards you or anyone else. I've never ran anything with a bored motor and I'm just trying to gather as much info on it as possible.11:1 416 is what I plan on building so glad to hear the 93 will be good! I have no sparks key either, I decided to hold off with installing one since the bore kit and key will generate too much heat.

[trailrider894]

Originally posted by 99400esex
Ok thanks man. I meant no disrespect towards you or anyone else. I've never ran anything with a bored motor and I'm just trying to gather as much info on it as possible.11:1 416 is what I plan on building so glad to hear the 93 will be good! I have no sparks key either, I decided to hold off with installing one since the bore kit and key will generate too much heat.

Its people like you who make this forum enjoyable and easy to get good information out of. I would suggest doing more re-search on this and maybe use the search button.

[99400esex]

Originally posted by trailrider894
Its people like you who make this forum enjoyable and easy to get good information out of. I would suggest doing more re-search on this and maybe use the search button.

Oh trust me I've searched the subject a ton. Just wanted some up to date opinions. If it wasn't .for the people I ride with I wouldn't even consider boring it. It's too hard to keep up with two 700xx's! But with the stage 1 cam you be surprised how much better I can pull on them through the first 3 gears. Mostly due to traction issues on there part but the cam made a big difference.

[2001400exrida]

Originally posted by trailrider894
ignore his comment. Nobody is getting anywhere by being a bunch of smart@$$'s while arguing.

trail you seem to be a real problem these days bud.

There's absolutely no reason for you to tell anybody to ignore comments, you are in no position to administer this.

I'm giving my personal experience and my 11:1 416 does not run good on 93 octane, i felt free to share this just in case this guy thinks he can run 93 and finds out that it might not work.

sure several people on here are running 93 with no problems, i already know that as i'm sure the poster does as well. It's just dependent on jetting, and just a difference in mods or motors.

again, you can keep your own opinions that's fine but do not assume that someone is wrong and then continue to tell people to ignore them. that's not good for the overall knowledge of this place.

93 may be good for some with 11:1 and it may not run good for some with 11:1, such as myself.

we are not here to argue so please don't present bogus posts that say " just ignore him" maybe you should just ignore me, so that way you won't have to read my posts????

just a thought....

we're here to help not to say what's right or wrong.

[slightlybent47]

CJM you are overlooking the fact that a 450 is water cooled so heat is les of a factor on the 450.
My 416 121/2 – 1 with 450 carb, st 2 cam with p&p runs fine on 93 pump gas. But I chose to run a 50/50 mix of 110 and 93 pump witch brings me up to around 100-102 range. And the ex runs just fine on that. I also use some U4.2 witch is 105 octane strait out of the can at 100%.
Using race fuel seems to give me a little better throttle response but other then that it seems to run about the same as pump fuel.
It’s not as critical as everyone is making it out to be. A motor is designed to run on a range of octane fuels. Sure there will be a magic combination that will get the best performance but it will run fine on a range of fuels. You guys can argue all you want but your just wasting your breath few of you have ever put a bike on a dyno and did a comparison so you really have no proof of your clams. Same with my statement, I have no proof but it is just common since. I think your just looking for excuses to not do the build. Stop making excuses for being slow, ride it like you stole it and just get it done.

You shouldn’t be concentrating on how fast your bike is.
You should be concentrating on how well you can ride it.

[CJM]

Excellent point bent, I had forgotten about that fact.

[trailrider894]

Originally posted by CJM
Excellent point bent, I had forgotten about that fact.

X2

Bent that is part of the reason i have not done motor work on my quad yet. But i now feel that i can ride beyond my quads potential. I guess then its time to start tearing into the engine.

[slightlybent47]

Until you see a great rider fully use the power of the ex to its full potential. And when you do se one you quickly see how much more that bike is capable of doing then you will up your game and ride it like you are supposed to. I don’t want too point any fingers at anyone but most of us who want more power, can’t or are not using the power they already have. It’s sometimes funny to keep seeing people find excuses for there lack of talent and blame there being slow on there equipment instead of looking at themselves.
My point is you can put everyone on a top of the line best of everything on a bike and have it set up perfectly and they will find something that is not there fault.

Sure there are riders that need to move up to better equipment and the better the bike the better you can perform on it but you still have to let your balls hang and just gas it and get it done. Hay I’m guilty at times of it too.
Don’t over look your tires and what condition there in, even a slightly worn tire can keep you from hooking up and getting down the track. Making you think you need more power when it’s just worn tires.

I don’t want to brag but when I started back racing my first year I road a bone stock ex and I won almost all of my races. I was the only one riding a 400, everyone else was on a 450 and most of those were built 450’s.
Those same riders are now riding much better and are beating me most of the time now. Granted I don’t risk life and limb to win a race like I did when I was younger. And neither do the riders I compete against, but there skill level has grown quite a bit.

Now I feel like I’m being held back by the limits of my bike but it also forces me to find ways to get it done with skill instead of just horse power.

[99400esex]

I've been riding for 15 years, trust me I know how to ride. I'm not a pro or anything but I can hold my own. It's very hard to be competitive vs a 700xx with a mildly nodded 400ex. QUOTE]Originally posted by slightlybent47
Until you see a great rider fully use the power of the ex to its full potential. And when you do se one you quickly see how much more that bike is capable of doing then you will up your game and ride it like you are supposed to. I don’t want too point any fingers at anyone but most of us who want more power, can’t or are not using the power they already have. It’s sometimes funny to keep seeing people find excuses for there lack of talent and blame there being slow on there equipment instead of looking at themselves.
My point is you can put everyone on a top of the line best of everything on a bike and have it set up perfectly and they will find something that is not there fault.

Sure there are riders that need to move up to better equipment and the better the bike the better you can perform on it but you still have to let your balls hang and just gas it and get it done. Hay I’m guilty at times of it too.
Don’t over look your tires and what condition there in, even a slightly worn tire can keep you from hooking up and getting down the track. Making you think you need more power when it’s just worn tires.

I don’t want to brag but when I started back racing my first year I road a bone stock ex and I won almost all of my races. I was the only one riding a 400, everyone else was on a 450 and most of those were built 450’s.
Those same riders are now riding much better and are beating me most of the time now. Granted I don’t risk life and limb to win a race like I did when I was younger. And neither do the riders I compete against, but there skill level has grown quite a bit.

Now I feel like I’m being held back by the limits of my bike but it also forces me to find ways to get it done with skill instead of just horse power. [/QUOTE]

[2001400exrida]

yeah and it doesn't take long to need more power on a 400ex haha.

after a couple flat track races with my friends and their 450's i could visibly see the power difference when we would come out of the turns.

We would both be full gas and they would pull away from me, then i would have to go into the next turn hot in order to gain a little ground.

the 400ex's lack power, it doesn't take a rider long to yearn for more, especially when they are running with 450's.

I can ride my 400ex all the way to the max against them and like i said they will always pull me out of the corners, which is fine with me, i'm more a trail/harescramble guy but i'm just saying.

the ex lacks a lot of power compared to the 450's, if you put me on a 450 i'd be faster on the flat track than I am on my 400ex. that means i could use some more power if i wanna win :)

[Quadracer667]

ive been riding for almost ten years and ive raced harescrambles for the last two and my first year racing i raced my stock 400ex against moded 450's and i was leading untill i broke the shifter on the third lap. it is how good you are at using the power that u do have. ive tlked to chris borich and asked him what i need to help me out racing and he said practice pratice practice.

[ish416]

My 416 121/2 – 1 with 450 carb, st 2 cam with p&p runs fine on 93 pump gas.

I am not sure how you can run 12.5:1 compression on 93 without retarding the timing.

I have similar mods except a different cam and an FCR carb. I can get away with running 93 in the middle of winter with the carb jetted properly but it still seems to ping under load. I am at about 1,100 feet above sea level.

[slightlybent47]

Originally posted by ish416
I am not sure how you can run 12.5:1 compression on 93 without retarding the timing.

I have similar mods except a different cam and an FCR carb. I can get away with running 93 in the middle of winter with the carb jetted properly but it still seems to ping under load. I am at about 1,100 feet above sea level.

Well it doesn’t run quite as good as a higher octane and I do feel a little more heat coming from the motor but it still runs quite well on the 93. I have played with the octane a bit and it seems to run best around 105. I’m at 200 feet above see level so that may have something to do with it. I don’t detect much pinging when I run the low octane but it dose get a little hotter. Also if I go to 110 it starts getting hotter like it does on the 93. I would not run it more then a few laps if was hot out on the low stuff.
I wish I had a laser temp gage so I get a better reading on the temp.
I would say what ever your set up you can run a range of octanes within 4-5 octane numbers and be safe.

[2001400exrida]

yeah, 12:1 and 13:1 don't run 93 worth a crap. are you guys really that tight that you can spend the money to do the high comp mods, but you can't afford the proper fuel for them.

i have run 110 straight in my 11:1 and it certainly doesn't get hot, i think it runs just fine, i do run a 100 octane of 89/110 mix to save an extra buck, but i can't believe you guys with 12:1 and high comp are running 93 that's not good IMO.

[slightlybent47]

Yeah I agree, to do motor mods and then not spend the extra money for the proper fuel doesn’t make since.
I think the issue is some people don’t have access to race fuel without traveling a long way to get it. but the reality is the better fuel runs best a moded motor.
And I don’t ride all that much so a 5 gallon can of 110 split half and half with 93 and it goes a long way.
I run 105 all the time but the point is there is an octane range that all motors will run on.

[CJM]

The higher octane gas needed is the main reason I didnt do a 12:1, well that and the heat.

Here its hard to get race fuel and $$$. For someone like me who rides every week (when its warmer) at least 8 hours its not worth it imho. I burn thru a tank of gas in 8 hrs no problem..

But if your gonna race or really want the engine mods you gotta pay for the proper gas so it runs right. There are days I wish I had a 450r since its water cooled, but then I remember just how easy the EX engine is to work on and modify if you know what your doing. Plus side is withjust air cooling you dont have to worry about a radiator, coolant, etc. Eliminates alot of possible headaches for those who dont know as much as well.

[ish416]

I ran 93 in my EX long enough to go across my field and back.

I have been running E85 for the last year and before that I was running 100LL AV gas.

The 100LL seemed to run a bit cooler than the E85 and also got better fuel economy. But 100LL is around $4-5 per gallon and E85 is around $2.30-2.80.

As far as the ops question of what can you do to a 400ex to make it run with a 450 without boring and still running 87 octane, the answer is you can't be competitive motor to motor.

However, put the money into the suspension and then you can use all 28hp that your ex puts down more than someone on a stock 450 can. They will still catch you on the straights rather easily but you should be able to more than overcome that difference in the woods with the right suspension and tires.