450r carb inprovement?????

[sburton1]

hi guys ive got a 400ex with a full exhausts,wb rev box,uni filter,and no air box lid,jet kit. could i expect a noticable differance with the 450r carb? if so how much inprovement did you guys get? like 3to4 hp? just wondering. ive also got a stage 1 hotcam coming maby that will go good with the carb thanks for the info guys!

cole

[CHEVYZ]

One of the best mods I have done so far. Not only will it improve overall power, but also gives much better throttle response, makes it run better and smoother... everything.

[QuadJunkies]

Originally posted by CHEVYZ
One of the best mods I have done so far. Not only will it improve overall power, but also gives much better throttle response, makes it run better and smoother... everything.

Well worth the $$

About a 4 HP gain and I agree... the throddle response is sooo much better!:macho

I love mine !

[sburton1]

thanks guys got a chance to get a 40mm edblebrock carb for a 450r at a reasonable price would that be better and still work ? thanks guys

[QuadJunkies]

If I was you, I would get the 450r Carb. Im sure there is alot of happy edelbrock peeps out there,but from what Ive seen of them I wouldnt buy one :uhoh:

Are the prices comparible?

[sburton1]

now the big question is will the stock 400ex throttle cable fit the 450r carb?? or do i have to get a new cable?

[sburton1]

and no not realy comparable but if it was gonna be a big differance i would have gottn it ill just get the 450r carb.

[QuadJunkies]

There really isnt that much dif. IMO to justify the Edelbrock for an EX .The 450carb should be a great pick :)

Here is a topic way back when I got on my carb, I think the topic is very useful.

Tina

450r Carb info (http://www.exriders.com/vbb/showthread.php?s=&threadid=143853&highlight=450r+carb)

[GPracer2500]

4hp?

[QuadJunkies]

Originally posted by GPracer2500
4hp?

YES. There has been testing done and shown :)

[fasterthanyouex]

Are people talking about people using s 450r carb on a stock 400ex motor or at motor built up a bit?

[QuadJunkies]

Now that is a good question!!
I havent read about it for a bit now , I want to say that was on a built motor, but dont quote me on that.

Either way... Your going to feel a nice change even in stock form

I have a 440 and Noticed a BIG change in throddle response and overall gains.

Ill have to look up the write up and Ill post it when I find it ;)

[sburton1]

thanks for the links and help quadjunkies!!! that helped out alot!!

[QuadJunkies]

GREAT! :)

I found the info on the testing, but its listed on another site:uhoh:

[QuadJunkies]

Here another topic about it

http://www.exriders.com/vbb/showthread.php?s=&threadid=142331&highlight=450r+carb

[sburton1]

ya found the results good info!!!

[sburton1]

so is the 400ex fuel hose two short?? or what? and trying to figure out which hose is the right one to order from service honda cant quite figure out the right microfich part number. also what dose the hot start cable do and do i need it hooked up to work on my 400ex?? thanks yall yal have been so helpfull.

[QuadJunkies]

Originally posted by sburton1
so is the 400ex fuel hose two short?? or what? and trying to figure out which hose is the right one to order from service honda cant quite figure out the right microfich part number. also what dose the hot start cable do and do i need it hooked up to work on my 400ex?? thanks yall yal have been so helpfull.
We had the 450r carb hose and no- the Hot start does not need to be hooked up ...It doesnt DO anything since its not on a 400ex :p ;)

I THINK it talks about it on the 1st link I gave you but not positive .

[wilkin250r]

Originally posted by GPracer2500
4hp?

I'm with you, I would have a hard time believing this on a stock 400EX. I could probably imagine a dyno showing a quirky boost somewhere in mid-range, but I don't think I could buy into a peak HP gain.

However, if you're talking a MODDED motor, I would certainly believe it.

[QuadJunkies]

The testing was done on a 416ex so it was modified ;) The runs were tested on a stock Carb vs the 450r Carb

I doubt you will get that much HP out of stock as well, but the Carb alone is well worth the investment compared to what you would spend on another aftermarket with similiar gains w/o having motor work done .

Ive seen the Carbs go for cheap on ebay.

[firefighterjosh]

Originally posted by wilkin250r
I'm with you, I would have a hard time believing this on a stock 400EX. I could probably imagine a dyno showing a quirky boost somewhere in mid-range, but I don't think I could buy into a peak HP gain.

However, if you're talking a MODDED motor, I would certainly believe it.

I am with you....What site is the testing on...I want to see it.

[mic 902]

Originally posted by QuadJunkies
Now that is a good question!!
I havent read about it for a bit now , I want to say that was on a built motor, but dont quote me on that.

Either way... Your going to feel a nice change even in stock form

I have a 440 and Noticed a BIG change in throddle response and overall gains.

Ill have to look up the write up and Ill post it when I find it ;)

Im running a 440 kit aswell. My stock carb has had work done to it, like taking the butterfly out and the choke removed and i think there is a bit of other stuff. Do you think that the 450 carb would still be worth it and if it is could you please give me all the details about jetting, needle clip position and putting the carb in?...... What to do, what not to do. Thanks in advance :D

[sburton1]

ya o picked up a 450r carb for 110$ shipped if you do a search for 450r carb and the user name quadjunkies you will find out so much info just start reading theres even pics to help you out thir is also a thread at the top of this forum called 450r carb jetting itll help ya out. ive still gotta figure out what jets to buy my self.

[mic 902]

Yeh thanks mate. Theres not really much point in me trying to buy a carb from someone on this forum since i live in Australia and not many people will ship to oz but im looking around locally. Also do you guys reckon a CRF450 carb would work aswell or not?? I can get one alot easier.

[sburton1]

well you can get one from ebay or from servicehonda.com service honda is like 165$$ new ebay about 100$$ but geting shipping is the key for you i see!

[mic 902]

Yeh thanks for the info. I think I have tracked one down so ill probably get it. Does anyone else here run a 440 kit with some port work. If you could tell me what jets etc. you are running that would be great. :D Thanks again guys

[QuadJunkies]

Originally posted by mic 902
Yeh thanks for the info. I think I have tracked one down so ill probably get it. Does anyone else here run a 440 kit with some port work. If you could tell me what jets etc. you are running that would be great. :D Thanks again guys

I have a 440 with P&P,Duncan PC4000 cylinder and a few other goodies. I think Im running about a 178(possibly a 175, I havent rejetted in awhile) right now and Im at about 2500 elev.

[CHEVYZ]

I am running a 182 down here with a similar set-up to QJ. :o

[krt400ex]

i would think that a 450r carb would be a bit too much for a stock bore 400ex. a 39mm FCR would prolly work better. just my $.02

[CHEVYZ]

Yeah, but you are also comparing a $100.00+ dollar carb to a $400.00+ dollar carb. It isn't the best, but it does damn good for the price you can get them at.

[krt400ex]

Originally posted by CHEVYZ
Yeah, but you are also comparing a $100.00+ dollar carb to a $400.00+ dollar carb. It isn't the best, but it does damn good for the price you can get them at.


ya, but ur talking about going from a 38mm to a 42mm on a stock bore. that's just a little much. it might work good if ur engine is putting out more top end power than anything, but for any other applications it's too big.

have u ever heard of the venturi principal?

a venturi is basically something with 2 openings that r diff sizes. in the case of a carb the first opening is larger and the second opening is smaller. what this does is allow more air at a high velocity.

the air is sucked into the carb and the air speed and valocity increases because the same amount of air is being forced through a smaller hole. to get that air through the smaller hole at the same rate, the speed of the air is increased. this helps to suck the atomized fuel/air mixture into the motor.

a smaller venturi will give u better throttle response and better bottom end, and a larger venturi will give u better top end and less throttle response. this is because at low rpms, when u crack the throttle, the air is basically forced into the cylinder. thus u get better power at lower rpms. if u have a larger venturi, at low rpms, when the throttle is cracked, the engine will be working to suck air into the engine. the result is less air and fuel in the motor and so u will be running less efficiently at lower rpms.

a large venturi is better for more top end applictions because, when the throttle is wide open and the rpms r higher, there is not going to be any restrictions and that engine is going to be sucking in all the air and fuel it can handle.so a larger venturi will allow it to do this more effectivly. with a smaller venturi, the engine will be slightly restricted on top because it won't flow as much air.

on a stock bore 400ex the 42mm is too big to give u any good bottom and or throttle response. a 39mm would be better.

i hope i didn't confuse u, i am not the best at explaining things. if u have any trouble understanding me, then talk to GPracer. he will understand and will be able to clarify better than i can

[CHEVYZ]

I totally understand that, and agree... but I was just commenting on why a person would choose the 450r carb rather than the FCR. To be honest though, I have used the Edelbrock carb before and find the 450r carb has better throttle response and bottom end even though the venturi is significantly larger on the r carb. You must also remember that the 450r carb is not a staight flow as is the FCR. I have not tested this on a stock engine, but I know people who have and have also benefited from it. To be honest, of all the carbs I have used thus far, the 450r carb has given me the best results... including the best throttle response despite the fact that it is larger than any other carb I have used. Again though, just commenting.... not arguing as for the most part I agree.

[krt400ex]

Originally posted by CHEVYZ
I totally understand that, and agree... but I was just commenting on why a person would choose the 450r carb rather than the FCR. To be honest though, I have used the Edelbrock carb before and find the 450r carb has better throttle response and bottom end even though the venturi is significantly larger on the r carb. You must also remember that the 450r carb is not a staight flow as is the FCR. I have not tested this on a stock engine, but I know people who have and have also benefited from it. To be honest, of all the carbs I have used thus far, the 450r carb has given me the best results... including the best throttle response despite the fact that it is larger than any other carb I have used. Again though, just commenting.... not arguing as for the most part I agree.


i wasn't arguing either. what i said was based on what i know, not experience. in my opinion experience makes for the best knowledge. not just facts and principals

[QuadJunkies]

Originally posted by CHEVYZ
I I have not tested this on a stock engine, but I know people who have and have also benefited from it.

And for the price, I would say its worth trying . I too have read the same and reported good results.:)

I would LOVE to see some testing just to see out of curiousity.

[sburton1]

well ill be putting it on my stock bore in about a month or so im currently deployed in the desert and am rounding up parts for when i get back ill probly have to use some of the smaller jets with a stock bore ill sart out with a 170 or so and see how it goes!!