Input on the big bore kits for a Yz426f

So i want to get a big bore kit for my 2001 yz426f but im not sure how it would hold up cause I dont plan on just using it as a racing bike but also a trail and hill climbing bike. Now i know the big bore kits goes up to a 444cc bore (not sure if it get higher then that) but of course ill have to get the cams and clutch and other stuff but im also not sure which is the best place to buy the parts and what all needs to be done to the bike so it runs perfectly without having to worry about say the clutch going out or carb to small.. etc soo if you guys could be great if i could get some response haha.

btw probably wont do this till winter but id like to start saving up and figuring all the stuff ill have to get so i know how much ill need to pay.


UM im in the same boat as you i want to do the same this winter along with paint and plastic face lift if you will....i hope we both get some good info....Where in PA? Im about 40 min west from washington PA in ohio

Hey guys, I'm in Erie, Pa. I just did a complete rebuild on my 2000 yz426 and I thaught it was great for racing, woods, and hill climbing, but i wanted something more toward what your referring to with less weight, so I baught an 08 yz450f. I think for the money, you too would be happier upgrading rather than spending it all on the old brick. The 450f is awesome, has tons more power than the 426 and weighs as much as my 05 yz250f.

These bikes are great stock. Your asking for trouble with that many modifications and if they make a bigger bike, why bother. Just buy bigger.

yeh im feeling ya, but two bikes in less than 3 months the wife would have something to say about it......and i must say iv allways been a kaw fan so it would be a kx....but this thing was cheap and i miss racing and being on two wheels

yeah im somewhat near reading pa and i like the 426 because its unique dont get to see many riding around and i want to go bigger but not really much with a 450 cause if i get a 450 it mostlikely be a 2006 which i unfortunatly do not have the money to purchase one but one day i will which is why i want to do the shit for my bike cause another thing is that who gets to see a supped up 426 haha

I see your point and I know how it feels to have one of the last 426 beast alive. I love my 426 and wouldn't do a thing to change it. The power is so amazing, weather I'm at the track or on the trails. That's why I don't see why you would wanna spend so much money for such little gain. Yes, my 08 yz450 is faster, but mostly do to the big weight differance and the suspension

Well from what i have read if you go to the 444cc boar kit the only thing you really need to check is the bottom end and if your not going to the 13.5:1 compression the bottom end should hold up but im wanting acceleration which is cams gearing and pips then ill check the boar kit but information is allways helpfull to know before diggin into the project

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