highest 400ex hp wanted

[jeepin21]

Wanting to see other peoples #s with there 400ex, mine has a duncan national 440 kit with a fcr 39mm carb. put out 42 hp 31 lbs. Not to bad but wanted to see if anyone can do better. Any 460 strokers out there ?

[Wheelie]

I'm curious to see what my setup makes.

Highest I've seen is 51hp. 483 stroker.

400ex with mods easily have potential to have 65HP. A stock 400ex with a turbo has 48HP. If you had a big bore turbo 400ex I would say it could get to 65HP.

[zrpilot]

This is the highest I have seen. Actual dyno run.

Thanks Laz!!

heres one:
465, 41 fcr, stroked crank with a 12.5 piston custom machined reliefs and crown, stg 3 cam, custom exhaust, 1mm valves and ported.

i beleive rage atv got 53

[DAVYS DAD]

in2000 i had T/C racing build me a 490BB his mx cam,lectron38carb,and porting,i hit 36hp on 92octain.Afew months later he built me a 465 i hit 40hpon 92octain,all it had was a 40lectron,porting,and mx cam i was very happy but this was a long time ago im sure you guys are doing better than that in 2009.

LATER

[barton1398]

Dont mean to ruffle your fetters FoxHonda but you will never get 65hp out of a 400. A built 450r peaks out at 60hp thats the most i have ever seen on a 450 when i had my 400 42hp was the best i ever got out of it that beast was built. Just my 2cents

[S.A.J]

barton1398 if 60hp is all you've seen from a 450r then i sugest you take a look down the list of dyno runs on this section of the forums ;)

[RATPACK Z400]

There,s a guy sanddragging28 that says he has a 500ex that puts out 85hp with nos and a 426 ex that smoke s 450r,s is that funny or what!

4 stroke tech tole me their 500ex engines will make between 48-52hp depending on what you want.

[Wheelie]

I figure my setup in its current form is making about 45hp.

Originally posted by Wheelie
I figure my setup in its current form is making about 45hp.

I see you run a Sparks Key. Does it help? From what I here keys are bad for modded engines making them run extra hot and what not.

[Wheelie]

I love the Sparks key. Made a very noticeable difference throughout the powerband. The swap to Ethanol and the key gained me a solid 10% increase in power--if I had to guess.

My only outing so far with the key was with the jetting too lean so I can't give an accurate figure on difference in engine temps. I bumped the main circuit after that trip (went from a 230 to a 240), but haven't had a change to really test it out.

The combination of Ethanol (cools much more than gasoline), the cooling fan, and running 100+ octane fuel I feel should make the key plenty safe with my setup.

FYI--Honda changed the timing on the XR400 in 98' I believe. They pulled 4 degrees of timing and leaned out the jetting for emissions. This reason and my lower rod/stroke ratio compared to stock lead me to the conclusion that my setup would respond well to the timing.

[Tommy Warren]

i have a stock 300ex, can I go to ethanol? If so How do you do it? I figure it would be a good idea seem as 300ex's don't have a cooling system!:mad:

Originally posted by Tommy Warren
i have a stock 300ex, can I go to ethanol? If so How do you do it? I figure it would be a good idea seem as 300ex's don't have a cooling system!:mad:

Put a big oil cooler and biger oil tank in it.

Going to ethanol is stupid at less your engine is fully built "for drag". Look it up in the "Powertrain" sec and you will change your mind.

[Wheelie]

Originally posted by factory2


Going to ethanol is stupid at less your engine is fully built "for drag". Look it up in the "Powertrain" sec and you will change your mind.

I disagree. My quad is not a drag machine, it's ridden in the woods, track and dunes. Ethanol works great for day to day use.

Methanol on the other hand is for drag bikes.

[RATPACK Z400]

Can ethenal blow up! say riding getting hot on tank or hose sprays on motor and boom! is it more dangerous than gas?

[Wheelie]

Originally posted by RATPACK Z400
Can ethenal blow up! say riding getting hot on tank or hose sprays on motor and boom! is it more dangerous than gas?

In a gas can or fuel tank, Ethanol is actually safer than gasoline. It has a higher flash point and less vapors to ignite.

It's a very interesting fuel, some unique properties compared to gasoline.

It's good for high comprssion to.

I had a little 21 inch tall 2 stroke cag engined pocket bike with 2 boost ports in the cylinder, 1 boost bottle, carbon fiber reeds, race clutch, lightend fly wheel, +2mm ported, 17:1 compression, big bore alc carb, big bore 49cc on alcohol and nitrous with a drag pipe. I didn't have it long enough b4 selling it so I couldn't find out the bad first hand. Even if you have it set up to run that way like I did it's still supposed to corrode the cylinder wall and draw moister in.

[Wheelie]

Ethanol does draw moisture, but it doesn't corrode aluminum. Store it in a sealed can in a cool, dry area and it's no longer an issue.

A lot of people confuse Ethanol and Methanol, Methanol does corrode aluminum, Ethanol does not.

[Baracudaaa]

By far the best 400ex.

http://www.exriders.com/vbb/showthread.php?s=&threadid=397275

[Tommy Warren]

so nobody knows how to convert to ethenol?

[sc400ex_rider]

there are threads in the 400ex forum..............