426ex vs ?

[REDRIDDER]

Hey guys let me know how your 426exs are running with stock 450s and no i'm not expecting them to beat one but i would like to know how they compare in drags,yeah your asking why am i asking when i have the 426 kit but unfortunately mine is in rebuild mode and i haven't run her in almost a year and everything in my sig i just bought this year to get her up and rolling again.Why im rebuilding it is because the small end of my crank rod stretched and i had slap in the piston so i said ive always wanted the 426 anyways so here's im am $1200 later., mine has the LA sleeve in it witch will helps in cooling,one good thing about having your stock sleeve pressed out and the new in is that if i ever blow her up i have room to bore to the next size up to a 440.Any one give me your inputs on the 426 good,bad and the ugly,i want to hear all the stories of the 426exs.all 426 info is welcomed please leave me some good reading guys and thanks to everyone who leaves something useful

[underpowered]

well my 426, mods in sig has been very reliable. been together for 3 1/2 years now with minimal problems. right after i put it together i had head gasket issues, then i broke a shift shaft off last year, but other than that it has been great. with the mods i have, i can easily run with a stock 450, or a piped one as well. the power is awesome, pulls from idle to rev limiter. the single item that made the biggest differnce wast the carb. it was night and day from stock to the FCR, but the port job helped tremendously as well. when i got the bike, it was a fresh 426 with a WB XC cam. since i have installed the pipe, Hot cams stage 2, put a new piston in it (bore was still in great shape even after 3 years), put on the FCR and had it ported. i could not be happier with it.

[REDRIDDER]

fill this room with 426ex comments thanks underpowerd

[REDRIDDER]

man i figured that this question would have been answered 100 times by now,come on guys i know alot of you have 426exs alls i want is some insight on my question.tell me anything about the 426 anything please i like to read what others think or have done.ps do any of you guys have problems with this web site cause alot of the time it is slow as molasses and you go to send a post or something it says data base error its really pissing me off,or is it just me?one other thing about this site i wish they would change is their product reviews their older than dirt you guys agree?i don't even bother to check them any more cause its the same stuff over and over,i like to read product reviews but not the same ones over and over i guess i'm just pissed at this site right now cause of the time its taking me to look at things or to send post .I will say though this is still the best atv site you can find,just needs to be upkept a little more. like i said ive tried sumitting this post 8 times now and get the data base notification,grrrrrrrrrrrrrrrrrrr!!!!!!!!!!!!!!!!! !!!!!!!

[maddmatt02]

GET THE CARB! apperantly it is a huge necessity, because I ride a 460 11:1 big bore stroker with hot cams stage 2, P&P head and dropped a tooth up front, and with the stock carb I get beat by my girlfriends piped/jetted 04 YFZ w/K&N, no its not rider.

and that guy up there says hell hang with piped 450's with a 426......

[REDRIDDER]

thanks matt i have the edelbrock carb now its getting sent back to them so the can bore it out and repalce the stock 15e needle with a 21e they say the 21e is for the 426ex,well see if their right

[400Trooper]

REDRIDDER

Dude thanks for your posting. I'm considering a 426 upgrade to the stock 400ex and wasn't sure of the total outcome. I've decided to go for it, add a 450R carb, HD head studs, HD timing chain and full exhaust. Still unsure of rev box.

I previously considered a hybrid CRF450 but decided to costly!

I race in the desert and literally raced yesterday, was running with the 450Rs until the long straightaways, time for a change!

Thanks again
400Trooper (soon to be 426Trooper)

[pats2007450er]

:blah: :blah: :blah: :blah: :blah:

[jsmith2232]

With only the 416 listed in my sig, I can keep up with most of the 450's in the drags, most of it depends on the rider. On the track it's the same way.

[maddmatt02]

once again theres that carb, because I dont wanna brag but I do not suck at riding, I am pretty damn good, not the best, but definately better than some who Ive raced. and I always get the hang of things really fast. its like i know a kid who has a dirtbike and has for months, still cant jump without wrecking, cant wheelie, falls alot from rough terrain, first day I rode my friends dirtbike I was hitting the 3 foot table top, not a huge jump but pretty good for first day, first day of owning my R1 I could ride a wheelie a good distance, not completely balanced going a steady speed but not full throttle using only power to keep me up, I raced flattrack this last season and some of the pro open riders were riding down in my 4 stroke open class and I finished with an overall 8th out of 33, horrible in my oppinion but I guess it aint too bad for my first organized race season of any kind and it being on a quad I had not ridden until the first race and didnt own so I couldnt practice anywhere else.

I have a 39 mil FCR Im working on getting on there before I go to oregon, just need air intake tube adapter and AP diaphragm, already got the lead on the throttle cable, jets in the mail, and its been disassembled and cleaned so its ready to go, only thing is not everythings here and we leave the 16th and I work 6-7 days a week so its gonna be tough.

[4everhonda]

I have a 406ex with mods listed in sig. With a bone stock yfz450 with a 180 pound rider on it and me being a 235 pound rider top end we are exactly the same. Off the line i pull him for a little bit then he pulls me for a little bit then i catch back up at top. From mid to top the 450 def pulls a little better. This is only with a 406, With a 426ex and the right engine builder I'm sure you could take a stock on and keep up with one that has some mods.

[maddmatt02]

well, I got basically what you got, well besides displacement, even got a barnett dirt digger clutch, just dont have that carb yet, and I get beat by YFZ's, hers is way quicker than stock though. everyone should know the outcome in 3 weeks if I can get it done and dialed in by florence.

[ctheojr450]

I recently finished my 426 build. For the money I spent, I cant be happier. However, side by side with a 450-I would be faster on the 450. On a track, put me on either one and I will turn very close lap times.

[REDRIDDER]

tanks everyone for all your comments.lets here more theirs more than 10 426exs on this site,post any thing about the 426ex.

[sodbrother]

I had a buddy build my 440ex, port polish, stage 2 hotcam, edelbrock card, weisco piston..... and it ran like crap. Dyno numbers were very poor...

I then had the local ATV shop build me a 426ex, bought a used stock cyl and head in the classifieds and started from scratch. I now have a 426ex JE 11:1 piston, stage 2 hotcam, port polish, oversize studs, HD cam chain, Dyna ignition, KN filter and the two most important things 41mm FCR carb, and dyno tuning.

My 426ex was built over 2 years ago and I have not had one problem with it. The bike runs very well with great power throughout.

I have raced several quads with several different riders. I can consistently beat piped 04 - 05 YFZ's and 450R's and stock Raptors 660 and 700, I have beat a few 06 piped 450R's, most well tuned modded Banshees on the other hand are a few links ahead of me.


If you want your bike to run the best you need to sell that Edelbrock carb and get an FCR carb. Hond and Yamaha are using this same style carb on the new 450's for a reason, they are the best carbs out. Whe you get the quad put together I stongly suggest you get it Dyno tuned by a mechanic that is familiar with dyno tuning quads.


I am thinking about trying out a lightweight flywheel and possibly a 12:1 compression piston. I am also planning on winning the next quad of the month contest.

[maddmatt02]

never let anyone who isnt EXTREMELY knowledgable and have the right equipment to test the results EVER touch your ports. thats probably what screwed you right there. because putting some rings on a piston in the correct order/gap spacing and throwing it in a cylinder can only be so difficult.
cam installation has no differences in quality, its either installed correctly and works or it aint gonna run or somethings loose and it runs and then fails. of course bearing clearances could be checked but thats mostly for reliability, not power. Ive heard mixed reviews of the edelbrock carb anyways. you sure timing was correct? (not sure how far off if any it can be before valve/piston interference) carb tuned correctly? what cr was the 440 kit? was the wiseco piston correct for the bore size of the cylinder?