400ex rebuild?

[backwoods 400ex]

Hi i have a 2006 400ex with a lexx pipe,uni air filter,dyno jet 160 and 38, and an open air box. Which will be the best option?
A: JE 10.5:1 with a Stage 2 Hot Cam
B: JE 10.5:1 with a Stage 1 Hot Cam
C: Wiesco 11:1 with a Stage 2 Hot Cam
D: Wiesco 10:1 with a Stage 2 Hot Cam
E: Wiesco 10:1 with a stage 2 Hot Cam and Sparks +6 key

and will i notice a big power gain to justify the cost??? i ice race and i need some more power to keep up with the 450s and i DONT wanna sacrifce reliabilaty cause in like 2 years im building a 450 but still want the 400 for trail riding and i need it to run on 91 octane

[99400esex]

Option c would be your best bet power wise. Many people on here run 11:1 comp and they seem to be very reliable. I like my stage 1 cam but a stage 2 would benefit you more if you are ice racing.

[honda400ex2003]

you cant go wrong with E, thats my exact setup now with the exception of a 450r carb on mine. 91 octane will run it all day long with no issues which is a great thing. I am hoping i wont have any issues with mine this summer when i go 440 stage 2. lol steve

[backwoods 400ex]

Okay thanks will option e give me the power to hang with the 450s? and with that one the stage 2 hot cam be to agresive?

[honda400ex2003]

would it run with a 450, yes. I would put money on beating a stock or lightly modded 450 with mine.

How do you want to ride? thats the first question to ask. any option is better than another depending on the circumstance. after you answer that, i will tell you my thoughts on the stage 2 vs stage 1 debate.

if it will just be an ice racer then the stage 2 will be a great combo. if you want to trail ride it too in the summer, then the stage 2 will also work great for a bit faster paced mid range style of riding. if you are looking for stump pulling power get the stage 1 no matter what the compression.

The only reason i recommend the 10:1 compared to an 11 is the 91. if you could get 93 then the 11:1 is fine with either cam. I think on 11:1 with a stage 1 on 91 it could be very thin ice. lol

steve

[backwoods 400ex]

Okay if i run a 10:1 with a stage 2 Hot Cam and a sparks key and ran 91 octane it be good for ice raceing and trail riding in the summer?

[honda400ex2003]

imo yeah it would be a great setup for just about anything.

11:1 wouldnt be bad either but will get warmer. steve

[crownandmonster]

I do believe that option E is the best route to go as Steve has mentioned, however, I do not believe that a stock bore 400 with a cam and sparks key will beat any 450.

[CJM]

E is nice, it keeps the stock compression ratio which means you can use the sparks key

C is what I have and I like it alot. I have no trouble beating 450's.

[PaRedneckRiders]

Even at 10:1 your bumping up the Comp ration iirc the stock comp ratio is 9:1.
I would personally go with C, i run a +3 key with my 11:1 426. And its not bad but if i putt or go slow enough that it wont cool itself it will still ping on 93. So when i get the chance i pick up some higher octane gas from a sunoco but the closest one to me is almost an hour away.

[backwoods 400ex]

Okay thanks for all your help im undecied between c and e... which one would be the best for power and be able to run on 91?

[CJM]

Originally posted by backwoods 400ex
Okay thanks for all your help im undecied between c and e... which one would be the best for power and be able to run on 91?

Why cant you get 93 by you again? But yes, C will run on 91 octane no issue.

[backwoods 400ex]

The highest pump gas is 91 but im gunna get some vp race gas for when i race would i be better i mix some like 98 race gas with 91 and run that all year? i just wanna be able to fill up when im out on the trails without carrying gas..or would 91 with a octane bosster work too?

[honda400ex2003]

the way i see it... 10-11:1 really isnt enough to worry about. 10 will be much more reliable in a race atmosphere where heat will build up quite a bit more. the longer it can be prolonged the better. I ran E with a stage 1 setup, and beat C when i had it.

with the stage 2, 3 degree key, and the 450 carb with my 10:1 i would walk all over an 11:1 stage 2 w/o a 450 carb or key. add both of those to a 11:1 and i think it would be just about the same race with the better rider winning. just like anything else.

I would say that how an engine is broke in would have more effect that the little bit of difference in compression.

others see it differently than I though... which makes for a good convo about it.

steve

[backwoods 400ex]

Okay thanks im gunna go with e or c and hopefully i can hang with 450s lol any other tips would be greatly apreciated THANKS

[CJM]

91 will run it fine Im sure.

Like steve said, all about how you do it. I went with what I did b/c I didnt want the sparks key or the 450r carb (thats later if I ever get around to it).

Altitude plays a huge role in it too, Im near sea level which i think helps a ton!

[backwoods 400ex]

Okay so just double checking if i got with the 11:1 and a stage 2 hot cam with hd head studs i can run 91? i live in central wi

[CJM]

Originally posted by backwoods 400ex
Okay so just double checking if i got with the 11:1 and a stage 2 hot cam with hd head studs i can run 91? i live in central wi

shouldnt be an issue. Ive ran 89 before with no issues

[backwoods 400ex]

Okay thanks but one last question i know i wont beta walk 450s but will i beta run with them? i race rubber class ice racing so skill plays a big part too

[crownandmonster]

This is just my opinion (I have had both 450r's and 400ex's), and I don't think the 450s are gonna run away from you like you are standing still, but I do think a bigger bore with one of the setups you have listed will benefit you the most. The other guys posting here saying that they can keep up with 450s (which is probably true) are all running at least a 416. When I had my 450 it was an 06 with an HRC cam and jets with an air filter and Full LRD exhaust with all other internals being stock and that thing was in an absolute different class than my 416 I have now. There was no comparison. Like I said I'm sure you won't get ran away from but, its gonna be hard to keep up on a stock bore 400ex IMO.