I was looking at the specs between the bike and the quad and there is quite a bit of difference between the two motor wise.

displacement compression ratio

bike 449 12.5/1


quad 439 11.9/1

it also lists the bikes carb as a 39mm fcr flatslide
and the quads as just 39mm fcr no flatside mentioned

 

On the Yamaha website it does say that the carb is a flatside on the YFZ 450, but the compression info. is interesting.

 

Yeah it is hard to say exactly what type of power it will have considering a little detuning but well all know before long were it stands in at on performance. I love my Raptor but I think the 450 will be runner also and i'm sure it will handle better in some areas - I hope that doesnt disturb anybody by saying that. Well see. SLIM

 

on the actual spec sheet it does not say that the yfz 450 carb is a flatslide

 

whats fcr stand for?? that may answer your question.

 

I'm sure it will handle better, and perhaps be slightly faster, stock...

but there is no way the 439 can respond to mods as well as the big 660

 

All you people will be very surprised how these motors "respond" to mods. I know this first hand and it will be VERY HARD for Raptors and DS650's to compete against these things!!!! If nobody believes me, just jump on a totally stock yzf400, 426, or mainly the 450 bike and tell me what's fast............ You have NO IDEA how fast a yzf400 with a 440 kit is!! Just ride one, and if the motor in the new Yamaha quad isn't detuned much, everyone is in for a BIG treat..... And so I'm predicting.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Not to mention in all around riding and not just straight line dragging the quad that's lower, wider, lighter and better suspended is going to perform better. You can dump all the money into mods you want but you'll end up spending even more on chassis and suspension with the raptor. I think over at atv-scene- they say the carb is an fcr but I'm not saying that makes it true. If you pipe, filtered and jetted the 450 I bet it would still make a ton of power. It's not like they cut the compression down to 10:1 or something and then destroked it to 400cc. They said you could interchange everything from the bike to the quad so you could by the bike piston and crank.

I don't compare modded quads because then it your creation and it's performance equals how much money you have and the quads are no longer the quads the manufacturer made. I think to compare this quad and that quad it must be stock for stock. I think ATV Sport wieghed a wet Raptor and it weighed 441 pounds. I'll be wet the 450 wieghs 375 or less.

 

This engine is between the YZ450 and WR 450 in tune, direct from yamaha tech

"Perhaps the most exciting news comes from the the YFZ's power-plant. Yamaha didn't tame down their world-leading four-stroke technology one bit. Instead they went all out and delivered a power-plant that all ATV racing enthusiast can be proud of. Yamaha watched the National ATV racing scene closely and made sure the YFZ passed all the AMA/ATVA standards for closed course competition. Yamaha skipped the reverse gear, shelved all unnecessary parts and went full-on race!

The 439cc liquid-cooled DOHC engine is very similar to the YZ450F engine, which means it rips to say the least! It snaps to life via electric start, but the motor has all the hardware ready for a bolt on YZ450F kick starter, and the YFZ's carb awaits Yamaha's hot-start button. This means serious racers will toss the battery and all the electric starting hardware, shed over twenty pounds of dead weight and start their race quad with a kick. Yamaha's kick starter accessory even includes a template for cutting the perfect amount of material off the rear fender to allow your foot to pass by the fenders. Very considerate of them, wouldn't you say?

Many of the parts are directly taken fromthe YZ450F. No corners are cut for ATV racers. Those days are over! Five titanium valves, an all aluminum body - ceramic coated cylinder, ratchet type five-speed shifter, direct ignition coil, and magnesium valve cover all shared from the wicked fast YZ450F. The intake camshaft is the same as the YZ450F, while the exhaust cam shaft, with its easy start auto decompression cam pin and lever, is the same one found on Yamaha's WR450F.

The forged piston is based on the YZ450F, but is newly designed especially for the YFZ quad. Piston pin diameter is increased from the YZ450F, but a minimal piston skirt is used to allow the YFZ to rev to the moon! The compression ratio is 11.9:1 so you'll want to feed this monster at least premium unleaded fuel.

Yamaha's direct ignition coil is a first for an ATV. The ignition coil is integrated into the spark plug cap and timing control is provided by Yamaha's 3D map. The YFZ's race-proven clutch is based on the YZ450F but uses thicker plates for increase heat capacity. Thankfully, Yamaha uses the same magnesium quick-access clutch cover as the YZ450F.

Yamaha's comment on the motor, "We really feel that this is the ATV that everyone has been waiting for. Its power-band is right there with today's high tech motorcycle engine. It's definitely the quickest ATV available".

Also remember Yamaha already offer a 13:1 piston option and the YZ450 ex cam is a bolt HP increase.......... Carb is basically the same as the YZ............

Raptors and Bombs stand back: this quad once "uncorked" will rip like you won't believe...........

 

The beautiful thing about any comparison between the YFZ and the raptor is the simple fact that Yamaha has introduced two, yes two AWESOME sport quads. What other company has done so? Suzuki and Kawasaki couldn't produce even one by themselves and god only knows what has happened to Honda. Yamaha has made it so that you can own two Yamahas and cover the woods, mx track, and dunes and desert. Who else can say that? How many wives are going to get a new 450 for X-mas or aniversary?[img]i/expressions/face-icon-small-happy.gif[/img]