Join Date: Oct 2002
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Re: 2004 Yamaha YFZ-450 Dyno Chart
My 426 makes about 33 to 35 hp choked up from the dealer. If you remove the restrictors, throttle stop, air box boot, muffler baffle,,remove grey wire and ajust your jetting accordingly, you can get anywhere to 42 to 44 hp at the rear wheel. If you change the cam timing to yz settings you can get up to 45, and a different pipe could get you maybe 2 more. Your dealer was lying about the 45hp out of a 4 wheeler at the rear wheel, without some motor work. A stock cannondale only put out 33hp ACTUAL HP at the rear wheel. Even though a cannondale doesn't make 40 hp at the rear wheels, they're still pretty fast. And if you've seen this bike in action, you can tell already that it moves. The motor has potential, and the ability on the track to beat anything. Yamahas 400/426/450 motor design has more potential for power then honda's does. That's why they, and they alone own the 5 valve genesis design. If they had the head ported, bumped up the compression, (its at 11.9 to one) my bike is at 12.5 to 1. Installed a full exhaust, then you might see around 45 hp. And stock for stock yamaha's 450 motor makes more peak hp then honda's does.
But if honda does get off there lazy butt and makes something better (all around) and more reliable then this bike, then that's what I'll buy to replace the hopped up warrior for my trail machine. Anytime someone comes out with a new sport machine, it's good news for all of us. A "liquid cooled" 4 wheeler, with rebuildable shocks that runs like my 426 dirt bike........ Sign me up! [img]images/graemlins/burnout.gif[/img]