Just wondering how much HP a 400ex would have with

[Greg Z]

JUST wondering im not going to do it NOW but im just wondering because im not really familiar with HP gains on a EX

416 JE piston 11.1
Ported head
WB Eseries pipe
Stage 1 Cam
White brothers air filter
Ported head
Jet Kit

IM going to guess around 37?

[cals400ex]

your going to get two ported heads?? :eek2: no, just kidding.

i would imagine you could be in the ballpark with 37. if i had to guess, i would probally guess a little less, but i could be wrong. if you tune it on the dyno, you might be able to get close to 37.

[WKY400EX]

Most likely it would be less? I think that most 440 kits put out somewhere around 40RWHP, but with your setup, you would definetly see a huge increase in power over stock.

I'm actually going to be doing something similar to your setup. Everyone please feel free to critique it.

416 bore w/JE or Ross (true 11:1 or higher)
Hot Cams Stage 2 cam
Port & Polish
aftermarket head studs
aftermarket CDI
bored stock carb (until FCR)

I already have a Sparks X-6 full system and Uni filter. Where do you think I'd be with this work done? Thanks.

[shamisc]

Originally posted by WKY400EX
Most likely it would be less? I think that most 440 kits put out somewhere around 40RWHP, but with your setup, you would definetly see a huge increase in power over stock.

I'm actually going to be doing something similar to your setup. Everyone please feel free to critique it.

416 bore w/JE or Ross (true 11:1 or higher)
Hot Cams Stage 2 cam
Port & Polish
aftermarket head studs
aftermarket CDI
bored stock carb (until FCR)

I already have a Sparks X-6 full system and Uni filter. Where do you think I'd be with this work done? Thanks.

Dat'l be jus' rite ! The only thing I wouldn't do, IMO, is the rev box. The EX doesn't make any more power after 8000 or so. I see no real need to over-rev especially if you're going with a higher ratio than 11:1. Could be pretty tough on that rod!:( I personally wouldn't go over a true 11:1 with the stock rod, but that's just me!:eek:

[WKY400EX]

Yeah, I have never been a big fan or believer of rev boxes, but I thought I'd throw that in. Anyway, what kind of numbers will I see from that setup? What about a heavy-duty cam chain? Thanks.

[shamisc]

Not sure about the #'s. HD cam chain would be great. I didn't do it to mine, but should have b/c I'm all for reliability and every little thing like that helps. But, There will be one put in along with my stroker crank and 13:1 JE !:D

[Greg Z]

reason im asking is cuz when i get seriouse into racing i wanna keep up with the YFZ and TRX on my EX for MX but the thing is I dont think ill be using all of the 40HP on a MX track Dont think I need 40 HP to jump lol but it ouwld be nice :devil:

[WKY400EX]

The way I look at it, you never can have too much power. You may not always use that 40HP, but it's there at your disposal whenever you want/need it.

An important factor you must weigh in is cost. Some simply cannot build a full-blown 440 race motor and do it right, so they opt for a cheaper option. Keep in mind that something like the 416 isn't cheap, but cheaper than a 440.

Just my $.02.;)

[WKY400EX]

I've still had the idea of a big bore on the back burner, but I've heard that with a comparable setup, the big overbores don't produce that much more power than a smaller overbore.

I'm saying that for example, a 440 with porting, 11:1 piston, and race cam wouldn't produce much more power than a 416 or 426 with the same porting, 11:1 piston, and race cam. Basically, I've heard that the slight bore difference won't make that much difference in power.

Anyone else care to chime in?

[markk]

well im running a weisco 11-1
hotcams stage one
K&N filter with lid
Dynojet kit 170
port and polish
rev box

and i think im pushing between 32 and 35 give or take a little!

[markk]

on a 416 sry