A friend of mine recently purchased the YFZ450 and while it outperformed my KFX in a drag race it didn't leave me in the dust. We also swapped bikes for awhile and the only significant difference was rideability. His YFZ didn't feel any faster but it was much more uncomfortable. He also commented that my KFX was a better ride but he wont admit the speed difference is negligible. We are going to glamis this weekend and I hope to surprise him with my new mods. The more I ride the more I realize I bought the right Quad.

 

Whatever you say man....I love the KFX 400, but the difference in acceleration is huge. I have ridden both a Z-400 and YFZ450. I have also raced both of them on my modded V Force. I can leave a Z-400 in my dust with little effort but I consistently lose by a hair to the 450.

I don't want to bust your bubble because the 400 is a sweet ride and I would love to have one. But you are dilusional if you think that they are even close in terms of performance.

 

Maybe his bike is out of tune or maybe its the 50 pound wieght difference but one thing is for sure. Through all 5 gears he never pulled away aggresively it was more of a walk and im guessing with the pipe,intake,and rejet I just did I'll be the one doing the walking next time we race.

 

I raced a Z last year and the 450 killed me ever time in the race to the first corner, and out of every corner.

 

The one thing I did notice on the 450 was the lack of torque. It had great power, but not torquey like the V or the Raptor. He was probably shifting really early and not letting that sweet high reving 429 reach its peak horsepower. On that quad, shifting early would probably hurt you more than say a raptor due to the engine size. The raptor is more of a big "underacheiver" and the 450 is a little "overachiever". But to extract the power out of the smaller motor, it has to be revved.

BTW, I don't doubt your word that you hung with him. I just doubt that the other fella was getting the most out of his machine. I love the Z-400 and KFX-400 for what they are intended for. If you and your buddy do much trail riding, you will have the more enjoyable ride. He will have to deal with four annoying things in the trails: (1) The width of the 450 makes it harder to squeeze into tight spots. I know because I ride a V Force and it can get pretty tough sometimes getting through places with such a wide quad and the 450 is just about as wide as my Force (2) The suspension on the 450 is tuned for racing and is a little rough in the trails (3) No reverse means that he better not overshoot or he will be pulling on the grab bar a lot (4) The tight ergonomics on the 450 would wear me out (I am a big dude and it is just too cramped).

But if you guys go to the MX track, you should not talk smack as the 450 is better in every way in that venue and you will get your **** handed to you if you try to race him (unless your skill is much greater than his of course).

Just my aimless ramblings, but would love to hear others opinions.

 

Listen to Homedawg! The YFZ has to rev high to achive maximum power. Although I've never ridden a YFZ (nor a Z-400 or KFX400), but I do know that they rev up to 9000RPM. That's a lot of revving so it's maximum power is somewhere around that RPM. If he shifts it at say 5000 RPM, it won't have that much power in 2nd gear and whatnot...

I have a magazine with me (ATV Action) and it has a 400 high performance shootout between the 400ex, Z-400 and YFZ450.
Here is the data from a drag and an MX track

Drag Times (slowest to fastest and finishing speed)
400ex: 10.06 seconds at 51MPH
Z400: 9.81 seconds at 54MPH
YFZ450: 9.26 seconds at 58MPH

Lap Times on a track (driven by experts)
400ex: 1:25:0
Z400: 1:24:9
YFZ450: 1:21:3

This shows you that the YFZ dominates. This data shows us how quickly the YFZ accelerates compared to the other two. I read something somewhere that the YFZ can beat a Raptor on takeoff and for a long strip until the Raptor eventually overtakes it. With simple gear modifications, the YfZ will beat the Raptor under any circumstance. What are the differences in the Z400 and KFX400 anyways?

 

I'm confused on why the lap times between the Z400 and 400EX are so close??!!

 

This sort of reminds me of one of the other posts where a proud Warrior owner said,
"The Warrior will climb anything the Raptor will....and more."
LMAO!!!

And it is certainly true that a modified YFZ can take a Raptor....but then we aren't comparing apples to apples are we?[img]i/expressions/face-icon-small-confused.gif[/img] Why don't we compare a modified YFZ to a modified Raptor? Wouldn't that make more sence?

 

Well what I meant was that if you put a larger sprocket on the front on the YFZ it will still beat the Raptor on take off and possibly a long strip. If you do this to a raptor it may not have enough power to pull itself up to a speed fast enough to pass the YFZ...

But I've never driven a Raptor.
I think it's because the 400ex has more low end torque than the Z400 and it's lighter so therefore the laps are pretty close.

 

I am an ****.. [img]i/expressions/face-icon-small-tongue.gif[/img]