Stroke is better than bore unless you want to rev real high.

 

I've got sliced breads number and ride an 02 Raptor; so dont be jealous(scared) of the Yamaha. HAhAHA slim

 

Oh another thing, If you want to know if a smaller engine can produce power over a bigger displacement engine just refer to Four Stroke Wars Two and remember the Sparks 505cc Powered 400 ex that was doing damage. You cant judge a book by its cover if you know what I mean. SLIM

 

Everybody is talking about how much horsepower they think this new atv is going to make, but aren't you forgeting something--torque. Yes, it may make more horsepower than the raptor, but their is a good chance that the raptor will make a lot more torque than the yfz450. I think the raptors strong point is that it has good low-end torque. I'm not saying that torque is everything, but you have to take it into account here.

 

True true; Well know before long wether it will be the quad to beat or not. Then again there will always be some peckerhead who will talk trash about it; know matter how good the quad may be. SLIM

 

I had a sport bike-CBR600F4....that thing was a dog under 5000 rpms...but when it hit 5K, you'd better hold on[img]i/expressions/face-icon-small-happy.gif[/img]. Pulled, and I mean pulled hard up to 12-13K. I think peak HP on the 450 is going to be quite high in the power band, like that of sport bikes. Likely have to ride it hard and keep the revs up, unlike the 400EX which has lots of low end......just a thought.[img]i/expressions/face-icon-small-confused.gif[/img]

 

Exactly my though Paddz.

I think the YZF will be no-torque, all-rev. More like a 2-stroke than a big thumper. Look for instance, my bro has a Katana 600. (hey, it's his first bike). It produces 64.9 peak HP at the wheels @ 9750 RPM. A stock DS 650 makes 43.1 peak HP at 6500 RPM. What a difference you say?? The katana makes 37 HP at 6500 RPM. Whoo.

Peak torque on the Katana is 35.3 ft.lb. The Peak Torque on the DS is around 31-33 ft-lb.

Torque is what matters, horsepower is an energy and torque is a force. Force is what makes those wheels turn.

Horsepower sells quads, torque makes them win races. Horsepower is calculated by a mathematical equation with torque numbers.

A dyno (dynometer) measures Torque, not HP. Then the computer converts it into horsepower.

The equation for horsepower is : Torque multiplied by RPM then divided by 5252.

Don't believe me? Find a torque curve on a dyno graph and try it. Also notice that on every dynograph, the torque curve and HP curve will ALWAYS meet or cross at 5252 RPM.

So please, nevermind Horsepower, Torque is much more accurate. [img]i/expressions/face-icon-small-smile.gif[/img]

Jeff

 

I believe you, I believe you. Those Katanas are pigs BTW[img]i/expressions/face-icon-small-wink.gif[/img]

 

On the Yamaha Canada website it says that the yfz450 has a torque peak of 27.6 ft/lbs at 6500 rpms. Figure that out at 27.6 X 6500 / 5252 and that equals the grand total of 34.1584.......... hp. So much for the 40-50 hp everybody was hoping for.

 

It will still scream at 34HP!!!