how much HP

[jasonex]

how much Hp does a stock 400ex have? and how fast does it go?

[mooseracerX]

About 28hp and about 63mph.

27.2 I believe at the rear wheels for the 1999 - 2004. Speed wise if you push to the rev limiter in 5th with 15/38 sprokets, 20" rear tires and the 1999 - 2004 gear ratios your looking at about 72MPH

[k4f5x0r]

i realy doubt it will go 72 bone stock. most 450's will do about 70 stock so i doubt a 400 will do 72.

if anyone says a trx or a yfz does 78 stock go die. cause your completely wrong. my friends trx with cams pipe and hrc kit only did 78 at its best.

[Hondamaster5505]

When I was going down the abandoned road in centrailia (theres a trail from the coalmine where we ride that goes to it) I was close to maxed out. Maybe 500-1000rpm's left. Wasn't paying attention to the tach.

But, I hit about 62.7mph before I started to slow down.

I also weight about 218lbs.

So, with the room left and if it can pull to the limiter, my guess would be about maybe 65

[alex10]

My 406ex does 62 according to my Garmin GPS, but it is half blown so it should do 65.

[brian76708]

Originally posted by k4f5x0r
i realy doubt it will go 72 bone stock. most 450's will do about 70 stock so i doubt a 400 will do 72.

if anyone says a trx or a yfz does 78 stock go die. cause your completely wrong. my friends trx with cams pipe and hrc kit only did 78 at its best.

My 400ex with a knn and HMF pipe with 14 tooth front sprocket went 73 so i don't doubt at all a stock 400 with 15 tooth front sprocket could make 72mph.

and who gives a sh** that your friends trx does 78

[alex10]

73 according to what?

[brian76708]

tail tech vaypor and i was on concrete yes i would not stay at this speed for any period of time but it was possible if i was want to stay at resonable rpms i would ride around 67 mph

[bama racer]

64mph with a good tail wind

[Hondamaster5505]

Originally posted by bama racer
64mph with a good tail wind

HAHAHAHAHA. lmfao.

There is no way a stock ex with a pipe and filter and a SMALLER sprocket does 73. Im calling BS.

Check your tire sizes. The vapor doesn't compensate for different size tires, you have to set it to the correct tire size to get a correct reading.

Mines ser properly, I have stock gearings, a FULL exhaust, and filter and can get to about 65.

[HondaRaceReady]

My motor is stock and feels like it goes like 55 max, but I never clocked it and its an 07.

[project400ex19]

anyone know how fast you could go with 16/36 gearing? ATVs are officially street legal now here, so I'd like to be able to do about 70 at quarter to half throttle in 5th gear. I hit 70 with 15/38 pinned, that's side by side w/ a king quad 700.

My friends 440 stroker pulled 86MPH so never say never. And i'm pretty sure my quad goes faster than 65MPH

[brian76708]

i have the stock tires on

[Hondamaster5505]

Originally posted by FoxHondaRider
My friends 440 stroker pulled 86MPH so never say never. And i'm pretty sure my quad goes faster than 65MPH

See, this is what people don't understand. Motor has very little affect on top speed. It's all about GEARING. He must of had it geared fairly high.

That's like me saying that I have a 250ex that does 40 stock. Then I throw an exhaust big bore etc. But its the same GEARING. It will probably do about 45 maybe with the mods, which isn't that much higher at all. It'll just get there like a bat outta hell.

And your pretty sure? Well pretty sure isnt the same as sure. You might be surprised at what your actually doing. The gearing on the older ones was different, so you could possibly be doing 67-68 maybe.

Drive next to a car or get a speedo

[Hondamaster5505]

Originally posted by brian76708
i have the stock tires on

Yeah, but let me guess, you never changed the settings?

They don't read the stock sizes or bigger. Mine are 21's and I had to change the preset number drastically.

Measure your front tires like they tell you to, and then set it properly and see what speed you get

[alex10]

I went down a good hill with my 406 today with some 22in back tires and got 66.8 according to my Garmin GPS. I can tell this engine doesn't have the balls to hit the rev limiter though.

[krt400ex]

Originally posted by Hondamaster5505
See, this is what people don't understand. Motor has very little affect on top speed. It's all about GEARING. He must of had it geared fairly high.

That's like me saying that I have a 250ex that does 40 stock. Then I throw an exhaust big bore etc. But its the same GEARING. It will probably do about 45 maybe with the mods, which isn't that much higher at all. It'll just get there like a bat outta hell.

And your pretty sure? Well pretty sure isnt the same as sure. You might be surprised at what your actually doing. The gearing on the older ones was different, so you could possibly be doing 67-68 maybe.

Drive next to a car or get a speedo


just because he didnt mention that it had a gearing change doesnt mean it wasnt changed. if you put a rev box on it(common with worked engines) the extra 1000 RPMs will give it more on the top end without actually having to change the gearing.

my quad had 15/38 gearing stock and i am now running a 15/36. i am sure my machine will hit 70 mph wide open, but it has to be flat and smooth. you hit bumps or soft stuff and the machine will not pull through it as easily.

[krt400ex]

oh, and BTW, they make between 26 and 27 hp stock

Originally posted by krt400ex
just because he didnt mention that it had a gearing change doesnt mean it wasnt changed. if you put a rev box on it(common with worked engines) the extra 1000 RPMs will give it more on the top end without actually having to change the gearing.

my quad had 15/38 gearing stock and i am now running a 15/36. i am sure my machine will hit 70 mph wide open, but it has to be flat and smooth. you hit bumps or soft stuff and the machine will not pull through it as easily.

thats right it had a stage 3 hotcam in there, running race gas mix, +1000 or 1200 rpm i cant remember, 20" rear tires, and I forgot the sproket sizes. but it had no problem getting there

[witech]

3 piped stock engined 400exs. 5th gear and 18inch dyno tires.
I would like to add to the gearing verses speed question. Yes you can gear a quad to physically spin the tires to a faster speed but you also need the horspepower to overcome the increased wind resistance which increases much more the faster you go. Dont quote me on this but I think you need 4 times the horsepower to go twice as fast. Of course terrain,tires,wieght ,wind,and vehicle areodynamics will affect speed.

this is just a HMF slip on with 18" dyno tires

Originally posted by witech
3 piped stock engined 400exs. 5th gear and 18inch dyno tires.
I would like to add to the gearing verses speed question. Yes you can gear a quad to physically spin the tires to a faster speed but you also need the horspepower to overcome the increased wind resistance which increases much more the faster you go. Dont quote me on this but I think you need 4 times the horsepower to go twice as fast. Of course terrain,tires,wieght ,wind,and vehicle areodynamics will affect speed.

how far did they rev it though? couldnt have been to 9100RPM unless they have a 14 tooth front sprocket because that speed seems way too low check out the dyno i posted, thats reved to 9000 RPM

[beakerlsc]

my 99 400ex topped out at 68 with 20" razr's k&n filter (don't remember if i had the prefilter or the lid on or not) t-4 exhaust (don't remember if i still had the headers then) and stock gearing.. I don't remember where it was but I have seen a top speed calculator online for 400ex's and it said 68 for a stock one, not sure how accurate that is though

[witech]

Originally posted by FoxHondaRider
how far did they rev it though? couldnt have been to 9100RPM unless they have a 14 tooth front sprocket because that speed seems way too low check out the dyno i posted, thats reved to 9000 RPM
Interesting thing about the charts. You see where the peak hp and torque is at is where you will be topping out at a highest gearing. As reving beyond the peak you will be lower in power and therefore wont be able to push against the resistance as well. Its a little decieving to go by gearing charts and dyno as to what the machine can actually do in the real world. Be aware that not all dyno runs are done in high gear. We use 4th most often .