416 vs 440

[supernatural]

what are the advantages of either kit? i want to put some money into my 2004 ex. what do i need to do for either kit and which one am i better off going with? everything on my quad has been done except for motor work. i was told a cam and a 440 kit was the best but when i look at them people are telling me i need different things like a bigger carb. my question is what is better, what do i really need, and what am i looking to spend? i want to do this right if i am going to do this.

[XXXRACER165]

You should go with a 440 kit, even though it costs a bit more there is more power to be had than a 416 kit. You will need to contact Duncan Racing to do it the best way possible. Everything you need is through Duncan Racing.;)

[xtullyx16]

416 cause u could always go bigger if u wanted to

[JW450R1]

I went with a 440 kit,stage 2 hot cam,port and polish,and a new cam chain.WOW what a difference.Just got done rebuilding a my buddies,and it really pulls hard.I also had tojump up to a 185 main jet in the carb...
For the 416 kit.I'm sure it works good,but me personally i didn't like boreing it out like .80 over or more.
That's my opinion

[400eXr1d3rZ]

It's reccomended you get HD Studs with a 440 bore. There's little or no power difference in bore, the power is determined in the compression piston you use, cam, valves etc...not the bore, a higher bore just allows you to have a bigger piston. I suggest you go with the 416, I have it and it's done me great so far! Just make sure you torque everything down according to specs and you replace the valve seals (and gaskets).

[sideways]

a 416 kit can produce as much power as a 440 kit, and its higher revving. i have a 416 kit, and love it. the 440's have a problem with overheatin g and warping cause it thins out the cylinder walls almost too much. also the 416 keeps the reliabilitty of a stock motor, IMO its the best way to go

[XXXRACER165]

Originally posted by sideways
a 416 kit can produce as much power as a 440 kit, and its higher revving. i have a 416 kit, and love it. the 440's have a problem with overheatin g and warping cause it thins out the cylinder walls almost too much. also the 416 keeps the reliabilitty of a stock motor, IMO its the best way to go

Then how come my 440 revs just as fast as a 450R with an HRC kit installed

[JW450R1]

I agree with XXXRACER165
I was told the 416 was bored .60 over

[atvhonda-rider]

I've learned alot about engines and i've read ALOT of threads, talked to people with both. what it ALL COMES DOWN TO, IS HOW IT'S BUILT! What i mean by this is you could have a 416 12:1 compression piston, stg. 2 cam, +1mm oversized kibblewhite vavles and maybe a 450r carb or FCR carb and you could blow away some 440's and 450R'S. BUT you could have a BUILT 440 do the same. The way i look at it is.... the 440 kit DOESN"T ALWAYS have trouble over heating, but it does have a bigger chance because like sideways said, its a bigger bore which thins the cylinder wall, BUT if you were to do modifications or just plainly build it right it wouldn't have that trouble. I look at the 416 kit or the 426 kit a GREAT choice because if you do it right, (just like any bore, motor work etc.) it will be a great setup and can still keep with the 440's and 450's AND if something goes wrong, and you need to rebuild the engine, you still got that room to step up to a bigger bore such as the 426 or 440. So its basically down to how well it's built and HOW much money you put into it. If i were to do a 440 i would put so much money into replacing everything in heavy duty chains and bolts and making sure it was all aftermarket to run smooth because its a big bore, but on a 416 you can get away with not installing heavy duty cam chains and aftermarket valves, which you could i guess with the 440 but i just look at that as silly lol. So im really not disagreeing with the 440 or 416 comments on this page, but as i like to play it safe than sorry when it comes to your engine, just for the fact that it does determine whether you go anywhere or not! Just my 2 cents, take it or leave it :)

[underpowered]

Originally posted by XXXRACER165
Then how come my 440 revs just as fast as a 450R with an HRC kit installed

a good engine builder. thats why. but the truth is a 416 WILL rev faster than a 440. simple physics. less mass, moves faster, also less surface area.


how and engine is built is key. i have ridden 440's that are complete turds, and 406's that are rockets. the engine builder is key, and the parts used, tolerances, and all. a well build 416 will run with a decent 440. but remember, there is no replacement for displacement.

and duncan is not the best. everyone has their opinion. duncan may be the best to you, others will say FST, other wll vouch for sparks or TC, or any other engine builder you can think of and say they are best. personaly nothin beats work done by ME, the owner. there i jsut somethin about building you own motors. i am proud when i say i build my motor, and a few others.

but for a 416 vs 440. i say 416. runs great, a good revver, and still leaves room for an upgrade later down the road. 416 is 2mm over, or .080.

[JW450R1]

What is the max u can bore the stock ex cyclinder?

[400eXr1d3rZ]

Originally posted by JW450R1
What is the max u can bore the stock ex cyclinder?

426.

[atvhonda-rider]

yeah exactly, thanks underpowered.... and if the most you could bore a stock cylinder was 426, we wouldn't be having a conversation about 416 vs. 440 lol i think the 460 is the biggest you can buy easily, but you have to stroke it and do alot of mods... i've seen a 495 but it had a custom cylinder/head.

[Got Boost]

I have never seen a 416 that was built worth a darn. most 440 kits come with a new sleeve, so they aren't "too thin", and you could take a stock bore and build it right and run with a 406,416,426,440, it is all in how you tune and build motors. The average person's bike is probably running at about 80%, meaning there is some sort of tuning you could do to improve tq, and hp.

[JW450R1]

Originally posted by 400eXr1d3rZ
426.
right ,i think its more then .80.And if it is,that to thin for me

[sideways]

i had my 416 built by sparks last year, the gncc kit. redlines at 12,500rpm. produces 44 HP (if i remember correctly) at the rear wheels. i believe the motor was buil;t properly and tuned properly. i put a crapload of money just into the engine and lots of time on a dyno to get it tuned properly. to me it was worth every penny.
ive seen a lot of 440 kits that dont run worth ccrap, but they were probably thrown together without the proper tuning. if i had built my motor into a 440, i would have spent almost double the money in uprgrading the rest of the engine like honda said.
i agree that "there is no replacement for displacement", but there are other options other than the 440 that will produce the same numbers on a powercurve for less money

[atvhonda-rider]

thats correct, its all about what parts, how you tune it and how much money you want to dump in, and the 416 does run strong so does the 426, and like you said their cheaper in the long run.... if you dont mind me askin, how much was the sparks gncc kit? thanks

[PRBanshee]

I built a 400ex for my son. I bored it .80 over which makes it a 416. I then put a 12.5:1 JE piston in it and a Hot Rod stage 1 cam. The head was done by PR racing engines and the valve remained stock. It had a Pro Circuit slip on and an FCR 41mm carb ( 40MM would have been plenty) with a K & N filter. This thing would pull some built 450's down the straights and got the holeshot 90% of the time. I would not recomend going past a 426 which is on more bore past the 416. Remember any piston over 10:1 will require race fuel. Good luck picking the right mods.

[wilkin250r]

Like everyone has said, there are lots of factors involved. Let's try to simplify things.

A professionally-built 416 will be faster than almost any home-built 440. But a pro 440 will be faster than a pro 416.

With ALL the different factors involved, I would say this. If you plan on doing the motor work yourself, go with a 416. If you plan on having a professional do the work, then go with a 440, and don't try to do it cheap. If a professional is handling it, plan on at least $3000.

[sideways]

when all was said and done with sparks, my gncc kit ended up costing around 3200. that included shipping the motor to them and the cost of the dyno tests once i got the quad back together. that cost does not include the new carb (fcr 40) head pipe, slip on, and new clutch (installed after i got the motor back by me).
i dont race my bike anymore, so the money could have been better spent on some things other than the quad. riding is my escape from daily life, and you cant put a price on peace of mind