I want to do it right, how would YOU build it.

[gregrob]

Hi guys,
The knowledge on this forum is amazing and I have spent several days reading before I decided to post.

The first of many things I have learned is that the debate btw 406/426/440 has been going on for a while, and each having their pros and cons.

I'll throw some things out and maybe you guys will be able to point me in the right direction.

Let me say first of all the reliability is #1 for my build. The quad goes an a long yearly ride, all day up the mountain, camp for a while and back down, so nothing I do can jeapordize reliability.

Right now the engine is getting rid of a little oil mysteriously and I think it's time to freshen up the top end. A little more power never hurts either right?

Here are my thoughts so far, you guys can tell me if I'm off on anything or not.

Wiseco 440 kit
11:1 compression
Cometic steel head gasket
Head Studs
Stage 2 hot cam
Honda Bond on cylinder base
DIY head porting IF I can find enough resources to do a good job on my own. If not I will send it in, who do you recommend?
450R Carb
Rev box

Any tips or tricks for building the motor to be reliable? I have put a few engines together before and I know what I'm doing.
I plan to take my time on the build and break it in per motomans instructions.

Also, for jetting, I live at 6000ft elevation, and ride anywhere from 6000-8500ft. Any ideas on where I should start jetting? I was thinking a 45pilot/160 main and see if it's still too rich?

Also, I am not dead set against a 406/426 setup, I just would really like the added torque of the 440. I am not a skinny guy by any means and torque is my friend.
Terrain will be mostly trails and SAND.

sorry for the lengthy post guys, I just want to make sure I do it right the first time and I know you guys have a TON of knowledge to offer.
Thanks for the help!

Greg

[Old Head]

Well you missed the best kit out of them all the 416. Great reliability and alot more punch than stock. As for jetting your pilot may be alittle fat the main seems ok if its a keihin jet. But its just a guess from me cause i never had to jet above sea level.

[browng31]

I have a 415 JE and I like mine, I'm a big boy too and it hauls my arse around pretty good, lol. Also never underestimate head porting, it does so much more than boring... I had a friend do mine, he researched and found out exactly what was good for my setup, it's actually a pretty complex formula, anybody with a die grinder and some bits can't just go hoggin' away and do a lot of good, either find a template or a guide or send it, because i would have screwed mine up for sure. And if you can find an FCR carb, they are awesome, but not sure how much they run compared to 04-05 stock 450R carbs...Have fun, 400ex's sure are nice bikes if they're done right.

[maxamillion]

Dont forgot to buy a 2002 crf450 cam chain ($26) and I would also replace the valve stem seals while you are in there.

I went with the 406 (JE 10.6:1) piston so I wouldnt have to worry about ruining my connecting rod. For longer rides Im sure it doesnt get as hot as a 440 either. I noticed the 406 had quite a bit more torque over stock...I did end up dropping to a 14 tooth front sprocket for tight trails so I wouldnt have to slip the clutch so often. Now its a torque monster!

I would only have someone port and polish if youre going to using a good full exhaust, open airbox, and good carb.

[gregrob]

Thanks for the response guys.

I forgot to mention the bike does have a full exhaust system right now.
I also plan on the 450r carb regardless of which kit I go with.

What's the highest a 416/426 kit has every dyno'd ?
What about a 440?

Thanks guys

[gregrob]

Originally posted by browng31
I have a 415 JE and I like mine, I'm a big boy too and it hauls my arse around pretty good, lol. Also never underestimate head porting, it does so much more than boring... I had a friend do mine, he researched and found out exactly what was good for my setup, it's actually a pretty complex formula, anybody with a die grinder and some bits can't just go hoggin' away and do a lot of good, either find a template or a guide or send it, because i would have screwed mine up for sure. And if you can find an FCR carb, they are awesome, but not sure how much they run compared to 04-05 stock 450R carbs...Have fun, 400ex's sure are nice bikes if they're done right.

cool man, where did your friend find this info? How much difference did you notice?

Also, why the 450r cam chain? I wasn't planning on splitting the case, can the chain still be changed without doing that?

[Old Head]

Originally posted by gregrob
cool man, where did your friend find this info? How much difference did you notice?

Also, why the 450r cam chain? I wasn't planning on splitting the case, can the chain still be changed without doing that?

Not a 450r chain its a crf450 chain. and yes you just have to remove the right side cover and remove the clutch to get to the bottom of it.

[gregrob]

I see, thanks.

Why is the 416 kit considered the best of all? Does it make the power of a 440 kit?

Thanks.

[gregrob]

bump?

[HondaEXrider22]

Not to sure one the power, I believe it has more lowerend, but not for sure. I know the 416 is the most reliable and seems to be the most used. I am also planning on some motor work when I can get some money :devil:

[northwest Texas]

I'm just past where you are right now. My 400 had started to burn some oil and it was time to do some engine work as I already had the chassis dialed in.

So, it turned out I was already at a 416 which meant one of two things, larger sleeve (426cc) or back to stock (397cc) and bore it back to 416cc. I opted for the 426cc as I didn't see the point in boring out a new sleeve and I didn't want to go back to stock displacement.

I decided to go ahead and have it ported and polished and I went with a JE 10.8:1 piston. Also installed was a Hotcam Stage 2. It feels like a different animal now, doesn't bog in the sand like it did before.

I wish I could tell you about reliability but I can't. I've only broken it in and ridden it once since the rebuild.

I wish I could probably help you more but I'm telling you what I did and I don't regret a single thing. I can't see the reliability be adversely affected enough to be noticable.

Sorry I can't help you on the jetting but you don't sound to out of whack. I just went blank on what I've got. I think a 170 main and 42 pilot (too small) in the stock carb. I do have a 450R carb waiting to be installed but I wanted to use the stock and see if I could tell an improvement between the two. Although many say yes, I want to feel for myself the gain.

If you have any questions as I was pretty vage about what I've done, don't hesitate to ask.

[gregrob]

thanks man.

Do you have to get a sleeve for the 426 kit as well? Or do you just bore the stock sleeve?

[Wheelie]

If you want torque, stroke it. A stroked 400ex makes a demented amount of torque.

[northwest Texas]

I resleeved mine.

I've learned a little bit that you can go to 426 with the stock sleeve but it gets awfully thin by that time. It doesn't really make sense to not resleeve.

I'd love to stroke the engine but I don't really care to delve into the bottom engine unless I have to.

I guess it all depends on what exactly you're looking for as far as power.

[DF400ex]

Originally posted by Wheelie
If you want torque, stroke it. A stroked 400ex makes a demented amount of torque.

Does anyone have a dyno results of a stroker?