416 or 426

[rdw03400ex]

im thinkin of rebuilding my 400 this winter and wanna start doin some research now. i am undecided between the 416 and the 426. 440s out of the question ive heard to many horror stories. i have been told that the 416 with a nice cam and rev box runs better then the 440 anyhow. now im not out to beat anyone but most of my buddies have 450s and i would like to be able to keep up. so if anyone could give me any info on the 416 and 426 kit i would appriciate it. also what brand piston and cam should i start looking for. i have a friend who build bikes and says hotcams are junk. he says curtis sparks is the way to go but im on a tight budget and cant spend 300 for a cam, as i only have about 800 to play with.

[matt1106]

Go with the 416, if you figure $200 for the piston and sleeve, $150 for a hotcam, $30 for a head gasket, and u have to be looking at like $400 for shop labor, and no, you cant just bore the cylinder yourself, unless you work at a shop, but if that was the case you wouldnt be asking this question. Not to mention, you may need to rejet because of the cam, so ya you can probably do it on a budget like that, but if you want a true 416, to run with 450's, you will need to get a port and polish, but thats really pricey.

[gojk]

Originally posted by matt1106
Go with the 416, if you figure $200 for the piston and sleeve, $150 for a hotcam, $30 for a head gasket, and u have to be looking at like $400 for shop labor, and no, you cant just bore the cylinder yourself, unless you work at a shop, but if that was the case you wouldnt be asking this question. Not to mention, you may need to rejet because of the cam, so ya you can probably do it on a budget like that, but if you want a true 416, to run with 450's, you will need to get a port and polish, but thats really pricey.

A few of these numbers are a little high...

I think a JE piston is $150, you shouldn't have to resleeve for a 416, about $40 for a steel top end gasket kit, $160 or so for a Hotcam, and about $60 for a machine shop to bore the cylinder. If you do all of the disassembly/assembly by yourself you can get the whole 416 for $400-$500. With just the 416 my ol 400 can hang with almost any stock 450 and might be just slightly behind a piped 450 when the riders are equal..

[rdw03400ex]

thanks, i planned on doing all the disassembly and assembly my self. anyone got any info on the 426 compared to the 416?

[mitchamus]

This is more of just a question.
What about just going with a High Comp Piston and cam. Maybe carb. Anybody have any thought on this kind of setup?

[matt1106]

stick with the 416, the higher you go with the displacement the narrower the head gasket gets from the inside of the sleeve to the outside of the jug. I know a lot of people who have 440's and are constantly blowing head gaskets. And if it was me personally, i would just go with a high compression piston and cam, i honestly dont think the extra displacement will make that big of a difference, not to mention that you will be sacraficeing some reliability, with a bored cylinder because when the bore it the cylinder walls get thinner, and like i said the gasket gets thinner too, so the chances of blowing the gasket will be more likely

[jesseweaver]

i dont know nearly as much as the rest off the guys on here about motors and stuff, but i have a 416 with hotcams and a rev box, and its pretty fast, and i think it is faster than my cousins old 440. i know my when he had the 440 kit, he blew out head gaskets all the time. he was constantly working on it. it always had problems, until he finally sold it because it was costing him too much to fix everytime. if you want to keep up with the 450s you might as well not spend much on the engine now, and save some of that money towards a 450.

[jesseweaver]

the mods to my 416 are in my sig. does anybody know how that would do against a stock 450?

[matt1106]

from what i've seen i would say you would run with them pretty close, my cousins 426 beat a stock yfz 450 by quite a bit.

[XXXRACER165]

Originally posted by jesseweaver
If you want to keep up with the 450s you might as well not spend much on the engine now, and save some of that money towards a 450.

Well you got that part right but, 440's (if you build them right) are faster than 416 & 426's. And I never have to work on mine, it's pretty easy to maintain.

[matt1106]

I personally would rather put money in me ex motor than get a 450, i've spent quite a bit of time on yfz 450's and trx 450's and i think my 400 is much more enjoyable to ride, even if it is slower.

[XXXRACER165]

Originally posted by matt1106
I personally would rather put money in me ex motor than get a 450, i've spent quite a bit of time on yfz 450's and trx 450's and i think my 400 is much more enjoyable to ride, even if it is slower.

Right on brotha!

[honda8&3]

416 all the way! With a hotcam stage 2 and the 416 you can't go wrong at all IMO:cool: :devil:

[Wheelie]

IMO go with the 416, it leaves one more bore for a rebuild in the future. Also, with everything else equal, the power difference between a 416 and 426 would be barely noticable.

[rdw03400ex]

i think i am goin to go with the 416. just didnt know if the 426 would be worth the extra money.

[REDRIDDER]

what do you think I'm going to say...lol ..426 but if you do a 426 kit get the sleeve with it, the reliability factor will be much greater.plus a 426 with a re sleeve from LA SLEEVE can be bored out to a 440 before the sleeve is no longer usable.

[matt1106]

I think if he gets a 426, he has to get a new sleeve, i dont know if a shop would even bore the stock sleeve that much, and if they did, i dont think it would be very reliable, it would be pretty thin when they were done boring

[EX Stud]

i have had my 426 with stage II cam for almost 3 years, and i ride the crap out of it. I haven't had ONE SINGLE problem with it. I beat many 450's with mine even some with pipes. You shouldn't have a problem keeping up.

SHoot i haven't even had a problem with my 400ex since i bought it in '02.

[Helix]

If your going with a 416 do you have to replace the stock sleeve or will the new piston work in the original sleeve?

[fastredrider44]

With a 426, you don't have to sleeve it. Or a 416. I have a stock cylinder on mine bored to a 426 and I didn't sleeve mine. I also have a stage one hotcam. I like it pretty good. I can keep up with piped 450's, but not 450's with motor work. In the woods, I like the power of my 400 compared to the 450. I feel faster because I'm more familiar with the power curve I guess. I'm trying not to do too much more to mine so I can get a 450 in the distant future. Mods are in my sig.

[fastredrider44]

Oh yeah, My piston is 12.5:1. I run pump 93 through it too.

[Helix]

Do you have to bore the sleeve to move to a 416 or can you just install the new piston without any machine work?

[gojk]

You deff have to bore.

[JOEX]

If you don't want to or can't bore the stock cylinder another option is a higher compression stock bore piston as long as the cylinder is in good shape (to be determined by a competent machinist) eyeballing isn't enough.

If the cylinder is good it will still need to be honed for the rings to seat properly. A friendly machine shop will do it for a minimal charge...

[Helix]

Would there be a big difference in power between a stock size high compression piston and a 416 high compression piston. If the cylinder only needs honed I'm not sure if it would be worth going a head and punching it out for a 416 if there is a considerable power difference between the two.