highest hp for yfz

[440exnacsracer]

i was wondering how much potential do these motors have. how much power can you get out of them, still being reliable and an everyday rider? thanks
Ben

[Mobile Dyno]

I've seen 49hp. It was a tt racer:D

[Kennethyfz450]

i seen a 508 kit push 53 horses...


a few guys with 470 kits are lieing over at central when they say they have 50 horses...


because this guys 508 kit had a bunch of junk, but his website no longer exist, and i cant remember everything he had to do to get 53 horses...

[440exnacsracer]

thanks for the replies guys, i just needed it to prove a point to a guy i ride with who says that he can get his yfz to 60hp easy.:rolleyes: :rolleyes: just like another guy around here who has a raptor that does 130 in 4th gear:blah: i need some new riding buddies:ermm: :D

[EvilJester400EX]

All dyno's read different. I had a buddy whose bike is built just like mine, dyno'd 58hp and that was no boring or stroking. I dunno about 58hp, but it's up there close to it lol.

[JKWGA400EX]

hey there is a raptor around here doing 120-130.he drove it to long ruined the motor and rebuilt it.it ran on jet fuel,then he sold and the guy that bought it ran normel gas on it again,now im not sure what it pulls.that thing is so loud that u can hear it comin 1-2 miles away.im not joking

[ramp rida 55]

rear wheel horsepower is about 12% less that horse power at the crank. most companies advertise what power they can make at the crank but dont say. companies claim to beable to get 55-58 out of there quads but in reality it would be more like 48

[citizennobody]

Originally posted by JKWGA400EX
hey there is a raptor around here doing 120-130.he drove it to long ruined the motor and rebuilt it.it ran on jet fuel,then he sold and the guy that bought it ran normel gas on it again,now im not sure what it pulls.that thing is so loud that u can hear it comin 1-2 miles away.im not joking


Yeah, and I shot some wolverines when I went hunting with my uncle in Alaska with my 12 guage, what would you do if they were attacking your cousins...

signed Napolean

[cummingetit]

Originally posted by JKWGA400EX
hey there is a raptor around here doing 120-130.he drove it to long ruined the motor and rebuilt it.it ran on jet fuel,then he sold and the guy that bought it ran normel gas on it again,now im not sure what it pulls.that thing is so loud that u can hear it comin 1-2 miles away.im not joking

"Jet A" fuel is basically #2 diesel with less lubricity.

[AlbaKFX]

I ride with a guy who had a raptor, that got stolen, who said if he blipped the throtte in 5th gear sitting on the tank it'd lift up onto the grabbar.

Also, his 02 came with piggyback stock ressies, and his bike did around 40 in 1st gear.

[citizennobody]

My YFZ launches sooo hard off the line in a drag race that my tires arent even touching the ground when I switch to second. I mix my C12 with 91octane half/half.....too afraid to go full race gas.....

[Shocka400ex]

I once read an article and I can't quite put a finger on where but it was about The maximum # of horse power that you can get out of a 439 motor. You see, even after you install an intake that allows Maximum amount of air, an exhaust, cam mod, and exact jetting that will allow maximum amount of fuel without running too rich, There is only so much you can get out of a 439 displacement motor. Even if you add a piston cams etc.... there is only so much hrspower availiable. It was said that the max your going to get is 52 hrspower from a 439 displacement motor. This make sense to me. After reading this article I laugh at people claiming they are pushing 60 horses out of a stock motor. I'll try finding the article so you can all see for yourself.

[440exnacsracer]

Originally posted by Shocka400ex
There is only so much you can get out of a 439 displacement motor. Even if you add a piston cams etc.... there is only so much hrspower availiable. It was said that the max your going to get is 52 hrspower from a 439 displacement motor. This make sense to me. After reading this article I laugh at people claiming they are pushing 60 horses out of a stock motor. I'll try finding the article so you can all see for yourself.

yep, i fully agree with you. there is only so much you can get out of certain motor designs when naturally aspirated. that article sounds interesting.

[Kennethyfz450]

the dodriders wrote that article their has been a few yfz pushing 53 horses but they have a 470..

i know of one with a standard piston, stock cams but in moded position, port and polish job, thats pushing 48horses...

[ketchup]

Different dynos will yield different numbers on different days under different conditions. Trinity claimed their exhaust made 60hp on their dyno while Max Powers 508 stroker was in the low to mid 50's. Dyno. results are for tuning, not to determine accurate HP or TQ. 50+ HP is not unheard of for big bore and stroked YFZ's...60, now that would be something to brag about.

[Kennethyfz450]

my last post didnt make any since..

a few years ago the dodriders made a true 52-54 horses out of a 508..

a few months ago a few 470 kits thought they was the stuff but only a few tricked out 470 kits made it past 50

[rocketpig]

Originally posted by ketchup
Different dynos will yield different numbers on different days under different conditions. Trinity claimed their exhaust made 60hp on their dyno while Max Powers 508 stroker was in the low to mid 50's. Dyno. results are for tuning, not to determine accurate HP or TQ. 50+ HP is not unheard of for big bore and stroked YFZ's...60, now that would be something to brag about.

Very true. Dyno numbers are virtually useless when used as only a peak HP number machine.

They should be used as a tuning tool to make your bike run better, not make it put up a number for bragging rights.

You can't race a dyno sheet and since you can take the same bike on the same different dyno and see a 10% power difference under different weather conditions really shows how misinforming a dyno sheet can be when not studied properly.

[ks_yfz450_racer]

i am gettin 48.9 hp out of mine and i have only piped it, jetted it and put a k and n air filter on it

[crager350]

What kind of pipe is best for the YFZ?













White YFZ 450
Coming soon
Alba nerfs red
K&N
maybe yushi pipe

[protrax]

Rossier Engineering

[Holeshot36]

Max power got 52.6 hp out of their 508 using pump gas and porting. Everything else is stock, If you get a bigger carb, rev box, go with 12:1 instead of 11:1, and alky you could get alot more hp.

[crager350]

Originally posted by protrax
Rossier Engineering



Hey is there a web site to go to? Rossierengineer.com or ?







White YFZ
Coming soon
Alba nerfs red
K&N
Unknown pipe

[protrax]

http://www.rossiereng.com/

[ketchup]

Originally posted by Holeshot36
Max power got 52.6 hp out of their 508 using pump gas and porting. Everything else is stock, If you get a bigger carb, rev box, go with 12:1 instead of 11:1, and alky you could get alot more hp.

Stock CR is 11.9:1. 12.5 is about as high as you can go with pump gas.

[crager350]

Originally posted by protrax
http://www.rossiereng.com/

Thanks for that web site.



_______________
White YFZ 04'
coming soon
Alba nerfs red
K&N
Rossier pipe

[400exrider36]

lte (http://www.lteracing.com/) pipes are supposed to gain 12 hp peak to the YFZ with a k&n air filer with no lid, which would make it 50 hp (peak)

[ketchup]

Don't expect LTE pipes to make a true 50hp, that's BS. Plus, they're heavy and the Y pipe disturbs ehaust velocity.

[400exrider36]

yeah i suppose, is LRD any good or is rossier still better?

[protrax]

Go with the rossier , you will not be dissapointed ! , They are made extremelly well and make more power than the others

[400exrider36]

ok sounds good, thanks.. do u know how loud they are?

[droopylee]

I am pushing 55 RWHP from my YFZ450, and it is still a 439, but with alot of work done to it, and every dyno is different, but I have ran 55-56 HP consistantly.
All my work was done by Joe at Rossier Engineering and is a hell of a sponsor as well. So if you want a great engine, get a hold of Joe and he will get the HP up there.

[ChrisSekerak]

i'm not sure if your all stupid or what...if you go to ctracing.com just a pipe and jet kit puts the yfz at 48hp. So I'm sure 60-70 is within reach. You could stroke the motor, hc piston, oversized valves and a cam would put you over 60 i'm sure and that's just on a standard bore piston.
no standard atv will do 130mph I hate to tell ya. put up or shut up

[yamablaster24]

in motocross its whoever gets off the line fastest. on my 33hp 400ex i have holeshotted and beat built hybrids and 450's pushing 45-50 hp,

welll now im getting a YFZ so we will see.

what do they put out stock...38 or so?

[ChrisSekerak]

if your beating people with that out dated ex they should not be racing.

[slamdak8782]

"if your beating people with that out dated ex they should not be racing" Sorry bud but a stock or piped yfz or 450r is no matchfor my ex. It has 440 kit stage two cam 5 angle valve job and porting "my porting" It will race any piped 450 any day and probably win. I stomped the crap out of a 450r with a pipe by three bike lengths. Now dont get me wrong Hrc in honda or 426 cam specs in yamaha and its over but piped my ex wins as well

[slamdak8782]

Also when it comes too max numbers it has to do with a term called volumetric efficiency. Two strokes are more volumetrically efficient. Fourstroke at 100 percent effieciency makes less power than a two stoke because of more powerstrokes. However there is a level that will never be attianed because of friction and heat. I would say as an estimate 85 to 90 percent would be extremely efficient engines. For four strokes near to 100 percent efficiency would could be attained with proper size inlets "valves" The problem here is intake design and cam profiles. Different rpms require different diameters and lengths. There are so many variables because not only are you trying to get air in but also as fast as possible making design harder and harder. So this is why engines are designed for certain areas where they will perform. Many ideas have been posed to make dual purpose engines most notably honda vtec vvti and chevrolets new 4.2 inline that works on the same priciples. I digress

[ChrisSekerak]

are you kidding me?? A piped and jetted YFZ450 does not even come close to a 440ex. And don't tell me that your 440 revs just as fast either because THEY DONT. A honda 450r motor is a lot more tame than a yfz, but the honda's are still nice. Check out the specs on CT racings web site. Most of the people racing at the amateur level and even some pro's just race 450's with jetting and pipes, the main thing is suspension. But i'm not sure why I do not see anymore 440ex's in the bunch??

don't get me wrong your 440 is very nice, I used to have one, I loved them, the motors are just outdated right now. But they are a very nice bike.

Later homie

[EvilJester400EX]

I have only seen one 400EX that could do anything against a YFZ in a race and that was my buddy's TC Racing 400ex. To put it simple, it out-revved a 426 dirtbike engine in a 400ex frame.

My mechanic had a YFZ built identicle to mine dyno'd and it ran a 58.6 rwhp. Still at a 439.

[slamdak8782]

Well i dont know what to tell ya man i Beat the 450r 3times ina a row. then i raced another honda with the hrc kit. he got me by three bike lengths. by that time we had gone an eighth mile. Right now im in the desert but when I get back
I m going to put stiffer springs in the clutch because right now it will not handle the pressure of launching like the 450r will. Im not in any way saying the 400ex is more powerful mod for mod but the 400ex can beat a piped 450r. No slaughter a 450r with the right mods. Im running a mild set up right now but the biggest problem with the 400ex is the guides coming through the intake. I took mine down and polished the exhaust side to a mirror finish. Also i took the intake out about a half an inch all the way to where the o ring is gone and made a new gasket for it and presto that thing flows a lot more air and fuel im at a 192 main jet now so it has to be making a LOT more power than before.:D

i dunno about the yfz's motor but you can be pushin 60 horses easy with the the dirtbike motor and standard bore they are suposed to be the same so i dont know y you guys think you nedd a 508 to get up there

[sampleez]

yeah, but think about how much more the quad will loose at the wheels vs the bike.

and i think the bikes stock is like in the 50's. and quad is like mid thirties stock

[ChrisSekerak]

Yes I do understand that a stroked 400ex or a huge big bore kit compared to a stock or mild piped yfz would win.....the honda 450r is way more tame than the yfz in my opinion.
I was just stating that a built 440 compared to the new yfz piped is no comparison, I don't care if it has larger valves, cam port polish whatever, they just don't rev as quick.

[Doak450r]

Originally posted by ChrisSekerak
i'm not sure if your all stupid or what...if you go to ctracing.com just a pipe and jet kit puts the yfz at 48hp. So I'm sure 60-70 is within reach. You could stroke the motor, hc piston, oversized valves and a cam would put you over 60 i'm sure and that's just on a standard bore piston.
no standard atv will do 130mph I hate to tell ya. put up or shut up

yeah im pretty sure if you actually dynoed that it would only put out around 40-42 hp from the stock 37hp pipe manufactures lie about there number they inflate them so you will buy here pipe and obviosly your interested so it must be working.

[ramp rida 55]

this guy gets it. some of you other guys wont under stand untill you get your quad dynoed your selves

[Cody_300ex]

I've heard, just heard that the pros 450s are running around 55-57. and thats on a 450cc displacment. But the pros have the best of the best stuff, there getting stuff that will probably never be released to the general public. So it would be hard for your average joe to pull it off.

[slamdak8782]

If you get 52 rwhp on a yfz you are just about at the limit for a 450

[Kennethyfz450]

chris

no pipe is going to get you close to the 50hp mark like ct racing claims


go to www.trx450r.org

you will find several dyno runs *yfz and trx's) that are barly over the 50 mark and they have loads of modifications...


with all do respect you can not add horsepower on paper

sure the ron woods kit is supposed to give you 4hp and the lrd pipe is supposed to give you 8 or 9 that doesnt mean your going to get 12-13 more horsepower once you install the two mods.. the problem with the yfz is its already hot from the factory heck its hard to buy a cam for the darn thing.... can you imagine spending 400 dollars on some webbs barly telling any difference from the stock cams in the moded position ?