426 vs 440

[smitht316]

im about to get myself into a project but not sure what to go with. i am wanting either the 426 or the 440. I am just wanting to know the pros and cons of both. also i just bought a hotcam stage 2. ive heard both that you should replace valve springs and ive heard that you dont need to replace valve springs. im sure it would work without replacing but for how long?? any advise???

[TCracin440ex]

well im no engine builder by far...but i know that the 426ex is your last bore on a stock cylinder for one, for 2 ive heard the 426ex will run a little hotter due to thinner walls, for 3 you dont need a new valve job for either one if you get a drop in cam....you will only need a new valve job for an aftermarket cam that requires new valve springs, retainers, and valves


440ex kit that i know of are famous for blowing head gaskets...so you will want to get a heavy duty headstud kit for it unless...

[tchonda426ex]

It depends on what type of riding you are going to do. I have a 426 with a stage one cam and i have tons of bottom end. My cousin has the 440 and i can smoke him up hill climbs. Both motors were built by the honda garage and the only downfall to the 426 is that the 440 can get you on a straight, but not by much.

[latheboy]

I have a 426 with a stage 2 hotcam and love it. No heat problems for me yet!

[TCracin440ex]

Originally posted by tchonda426ex
It depends on what type of riding you are going to do. I have a 426 with a stage one cam and i have tons of bottom end. My cousin has the 440 and i can smoke him up hill climbs. Both motors were built by the honda garage and the only downfall to the 426 is that the 440 can get you on a straight, but not by much.

yea but if you change your cam or do some port work on the 426ex then it should beat the fugg out of a 440

[SandShark400]

hopefully will grt one or the other!

[redracer10]

I have a 440EX and on of my buds has a 426EX...If you dont care about the time your atv is in the shop and you just wanna win races definitely 440...If you dont want your 400 in the shop much and not near the power increase a 440 gives but still a substantial increase i'd go with a 426.... I tell you what though I have had a 440 in my atv for 7 months with stage 2 hotcams, 14:1 compression ratio pistion and It has only blown 2 clutches and I ride about every day for 1-2 hours. And that isnt bad for a engine that is constantly running that hot!! get the 440!!

[smitht316]

im not so much worried about drag racing and beating everyone. more of my concern is the power to pull up the hills that the stock 400 doesnt have.

[WickedATVer]

what do you run for gas with a 14:1 piston?

[redracer10]

u can use just super unleaded gas it wont hurt it much but i use race gas from rockymountainatv.com

[knight rider]

the 440 is famous for blowing head gaskets IF U PUT A HIGHT COMPRESSION PISTON in it mine is a 440 with 11:1 and stage 2 cam and all vales ans springs hot rods crank new bearing new clutch and i have som many hours on it and i dont have the heavy duty stud kit in it and i havent blown it up yet and a 425 to a 440 if u want a 440 to make it work right u need the stuff to go with it like stage 2 cam witch u have ,rev box,new carb this will make it proform like a 440 should. it makes sence

[SandShark400]

i've been looking at all the different bore sizes you can get a 400ex they include: 406ex, 407ex, 416ex, 426ex, 440ex, 450ex, 460ex, 465ex, 500ex

[SandShark400]

i've found 440s for only 180.00 on ebay with gaskets, sleeves and pistons and all the smaller sizes for only 120.00 and down. if you got the 440 would you need to replace gaskets, cam, cdi box and carb, or are these things just extra to help it run better. because after all that crap it makes sense to save up a little while and get a 450, not trying to be a trator or anything but...?

[CHEVYZ]

Gaskets are a must for any of them- you are tearing down into your engine all the same. Cam, CDI box, exhaust, carb, ect.- all that is necessary if you want your bike to perform right. If you can save for a 450... go for it! My 440EX beats my slightly modified 450r in some terrain, though even with the work I have in it, it is still capable of being beaten in other areas... a long open filed for example. If you can go get a 450r, then get it... it is superior. If not, then mod your 400EX. I personally would go with a 426EX if you aren't just going to be drag racing and what not. Sorry, but big-bores are a pain and the higher you go, the worse it is to get.:ermm:
If you just want more power, go with a 416 ( IMO), but if you are stuck between the two, get the 426.

[TRXman86]

do not go with the 440 kit unless you plan on buying a ton of gaskets. like Chevy said, big bores are a pain! mine is costing me over 1500 bucks right now... i am having the 440 kit removed to though and getting a new head, cylindar, and a bunch of other NEW goodies. get a 416 or a 426. there isnt a ton of difference between the two, but at least with the 416, it gives you some added comfort from the edge of the big bore. PLUS you have room to expand to the 426 if you ever decide to... just my $0.02


so if anyone is looking for a Stage 2 hot cam, used head and cylindar, shoot me a line :D and ill give details...

[zeppelin]

Originally posted by smitht316
im not so much worried about drag racing and beating everyone. more of my concern is the power to pull up the hills that the stock 400 doesnt have.
what kind of hills are you climbing :eek2:, a stock 400 should take almost any hill you can throw at it.

any way i would go with the 426 i have heard too many people getting pissed off at their studs and over heating.

[sportraxkid]

If you go with the 440 and want a reliable bike get the 11.1 compression piston. I have had a 11.1 compression wiseco piston and a stage II hotcam in my bike for the last 2 years and I go to the dunes allmost everyother weekend and run it on pump gas and I have not had any problems and it will beat stock or slightly modded a 450's up choke cherry or sand mountain.

[smitht316]

the stock 400 does fine if your just riding around out on the dirt doing some hills but ive had some hills down at the dunes that it just cant make it up

[QuadJunkies]

Originally posted by TRXman86
do not go with the 440 kit unless you plan on buying a ton of gaskets.

That is totally incorrect ... Its all in getting the CORRECT Gasket

Ive ran my PC4000 for 1.5 years and Im still on the original Gasket. IF you install the Kit correctly and withthe right kit, you will NOT blow gaskets.
I have a 426 kit for a back up and ran it for a year, I pefer the 440 over my 426 anyday of the week. The 426 does tend to heat up and loses much needed power ,the 440 will stay cooler