We just dynoed a brand new yfz with a slip on and it pulled 46rwhp after tuning . My 470 Cannondale pulled 70.02 on the juice about 20 minutes before. Charts are posted in the dyno section of Cannondaleriders.com

 

Most them are way off.

 

a stock yfz only has about 9 real hp. the weight takes the rest away.

 

dont shoot for dry weight on the 10 - 1 ratio. figure in rider and gear if you can get the hp in the 10 - 1 thats lots better.

 

ya know, draging takes a 'little' skill, but i dont' see how these #'s you guys are putting out that a 700 raptor has almsot 20 more hp then a yfz. I really wish i knew what my quad put out on the back wheels, but appearantly the yfz is way faster/powerful then a raptor b/c i'm fat =) and the dude i was racing was prolly not even 165. Basically, rear wheel testing each individual quad is the only was to really know what the hp is. If you jet it a little differently then someone else you'll have 1 or 2 hp diff, which btw is alot. Alot of factors contribute to how much these engines can put out.

 

o my bad, i won by over 5 lengths with a dirty air filter*. haha forgot to add that part

 

Rap 700 is putting out 42hp stock and thats a fact. A nother fact is that its only 686cc [img]i/expressions/face-icon-small-shocked.gif[/img]

 

Well you better call the executives of these companies and let them know that the engineers for their motors do not know what they are talking about. That you know better than the people that designed the engines what horsepower the engine is rated at. [img]i/expressions/face-icon-small-happy.gif[/img]

Imsamm, not sure where you saw 20 hp more. The manufacturer numbers only list it at around 8 hp. Highest hp does not always mean fastest, (although it does help). Even if you throw out the driver variable it still makes a big difference of how and when the engine develops its horsepower. The 450 engines rev extremely fast and hit their peak hp quickly, where your big bore motors take a little longer to rev, usually giving the 450's the jump off the line. Also the big bores do not like the high rpm's. That is why the guys on the big bores short shift them to keep them in the peak hp range. You get someone that knows how to short shift on a big bore and you will more than have your hands full.

 

Long Stroke vs Short Stroke.

 

My 660 raptor with just a slip-on was making 35 hp on the dyno and I forget the stock yfz 450's exact horsepower but it was about 1 horsepower lower than mine. A 700 raptor was dynoed too and it was around 38-39 hp. Don't hold me to the Yfz's exact hp but i definitely know that it was lower than mine. The yfz had the best low end, trx 450 had the best top, and the ltr 450 had the smoothest curve out of the three along with the lowest hp number out of the three.