426 or 440 ??

[atb7346]

I need to replace the rings in my 400ex. I was thinking about putting a 426 or a 440 big bore in it. Not sure which one is the cheapest or which one performs the best. I will probably be doing this myself, so I also need the easiest one as well. Thanks for your input.

[6858-400ex]

the 426 will have the differnt sleeve but u will not have to get it bored

the 440 will have to be bored over

[BLEEDRED]

I thought the 426 was the last bore on the stock sleeve?

Anyway a lot of people love the 416. It's going to be cheaper to go with a 416 or 426 but I love my 440. I did have to go with the HD head studs to keep the head gasket from blowing out. I also went with a CRF450 timing chain while I was at it. Whatever you do make sure you do all your homework before you start turning wrenches. Which is pretty much what you are doing right now asking questions in this forum. It's not that difficult, but without the proper research on gasket thickness and compression ratios you could end up with a slow revving slug. Also make sure you get a manual. I love my Clymer. Good luck and make sure you use the search option as much as possibe, all of these questions have been asked and answered at one time or another.

[redrider440]

[QUOTE]Originally posted by BLEEDRED
[B]I thought the 426 was the last bore on the stock sleeve?

Thats what I thought too, I could be wrong though.

[sickmojave]

yes 426 is the last bore on stock sleeve or you can buy a 426 sleeve that can be bored out to 440. ;)

[BLEEDRED]

Right, because I have heard people say that is not the best idea because the sleeve gets so thin with that bore and some people have problems with heat. I'm sure you can bore the cylinder and resleeve for a 426 but if you are going that far you might as well go with a 440.

[dirtmomma]

We were in the same predicament w/ our 400, had the 440 kit already BUT decided to go w/ the 426 due to the fact to get it to perform to it's best you need to have a good bigger carb,valves,cam ect. :) at least from the research I"ve done!!!
You get a new sleeve w/ the 440 big bore kit, the stock sleeve can be bored to 426, it's thin but everyone does it :) my hubby likes the results of the 426. We will do the 440 once this one is worn out & we can save up the extra $$ for the carb ect.

Good Luck :D

[EvilJester400EX]

Every 400ex that I've seen bored to a 426 blew up. I'd recommend a 416.

[RiderTRX400ex]

dont run higher than 11:1 on a stock rod....

[redrider440]

Originally posted by EvilJester400EX
Every 400ex that I've seen bored to a 426 blew up. I'd recommend a 416.


Wow that sucks. I ran mine for 3 years and never had the first problem with it.

[redrider440]

Originally posted by RiderTRX400ex
dont run higher than 11:1 on a stock rod....



Why not? I had 13.0:1 on mine and never experienced any type of problems.

[atb7346]

If I do get a 440 big bore kit, what is the best compression ration and about how much does it cost to get one bored out.

[BLEEDRED]

Most people would agree that around 11:1 CR is good on the stock rod and pump gaz. That is what I have and I am very happy with it. I paid $100 to have my cylinder bored, reseelved and honed. Plus you have the cost of the big bore kit, gaskets, other little things (O-rings, bolts as needed, exhaust gaskets, locktight, cleaners, tools as needed) some of which you may have and the rest you can get from service honda. I would also recommend going with a drop in cam like HotCam and a heavy duty timing chian (CRF450 timing chain...service honda $25). Unlike most, you are doing your research...keep the questions coming...:D

[atb7346]

do you ever have a problem with overheating? I can get a stage 2 hotcam, sleeve, gaskets, and a piston for about $330. Does that sound good?

[BLEEDRED]

Sounds like a decent price...what piston is it?

[BLEEDRED]

I have never had a problem with overheating, but it does run hot. I live in Michigan and don't ride often in the dead heat of summer and I also mostly ride woods. I also have the shrouds that help direct air to the engine.

[OldYellow]

Just go with the 416, everyone i have talked to has loved it, and you wont come close to going to thin on the cylinder wall.

[dirtmomma]

I'm curious on the cam :) a fellow racer suggested a WEB cam (451 grind i think) for our 426, we put a xr400 cam in it for now, just wondering why nobody suggests WEB cams, & it's always HOT CAMS?? :) I run a WEB in my 300 & it's been a GREAT cam(it ws even used) I have a brand new one to put in once this wears out but it seems to be wearing great!!
I guess the CRF450 timimg chain is better than a stocker huh???? Thanks :)

[BLEEDRED]

Is the webcam a regrind? (Stock cam that has been hard welded on and regound to webcam spec?) If so that is the reason...you need to have hardened rockers for that. HotCam is a drop in cam that does not require hardened rockers...

CRF450 timing chain is a lot more meaty. You hold it side by side to the stock 400EX chain and there is no comparison.

[dirtmomma]

Originally posted by BLEEDRED
Is the webcam a regrind? (Stock cam that has been hard welded on and regound to webcam spec?) If so that is the reason...you need to have hardened rockers for that. HotCam is a drop in cam that does not require hardened rockers...

CRF450 timing chain is a lot more meaty. You hold it side by side to the stock 400EX chain and there is no comparison.

:) Thank you for clearing that up for me!! I think they sell the WEB cams on thier site, I know you need a core cam, but yea i think now i remember you needing hardened rockers :D

[atb7346]

Weisco 11:1 piston and it is 280.00 not 330.00

[SHADETREE101]

i recently built a 416 on my ow 400 and it ran great. 11-1 je piston and a stage 3 hot cam drop in. it would run with any 440 it put it up against. the only thing i didn't like was so many people telling me you could or couldn't run pump gas. well, i had a problem with second gear and took the opportunity to replace the piston and now is the 426 13.3:1 with cheater gaskets on the stock rod. it never gets hot and i put around with two five years olds in first gear all day. when i drag race i can run with a pretty fast raptor that has the sparks pipe, k&n pods, and advanced timing. i have never had a problem with head studs, however i have to run 110 octane fuel now. the difference between teh 416 and 426 were only noticable because of the compression change. and yeah i spank the 440's now.

[sloppyjoe]

my buddy put a 440 in his bike. he spent $1700 in the rebuild. he did his the right way! he had his head ported and bigger valves put in. he had the carillo rod put in also. i am running the 426 in mine right now, i havent had a problum yet but i havnt had much run time on it yet. the main thing is to go with the heavy duty head studs, NO MATTER WHAT ANYONE TELLS U THESE ARE A MUST!! if i wre u i would go with the aftermarket rod also. if u dont put the heavy duty head studs in u wont be able to keep a head gasket in there, i'd go with the rod also just for a little ins.

[TC426EX]

Yes, do the rod for sure if you can afford it, or take the risk of learning the hard way like me...

HD studs and a CRF cam chain are 2 relatively cheap mods that should definitely be done. You can get a good set of studs from GT Thunder for like 60 bucks, and the CRF timing chain is only like 25 from service honda. And as someone above said, there is no comparison between the CRF and stock EX cam chains....

[mrg21201]

I am also thinking of upgrading to a 416 11:1 from stock. I also would like to do a hot cam not sure what stage to get. Maybe do the crf450 timing chain. Should i need bigger studs with just a 416? Any other suggestions? Maybe porting?

[sloppyjoe]

with the 416 u really dont have to go with the bigger studs. my buddy has a 416 and that thing rips. he doesnt have the port work but he does have the stage 1 hotcam & 39 fcr. he has the stock timing chain. with the dmc exhaust. i think his is 11:1 je piston.