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View Full Version : Cutaway pic of YFZ 450 motor



GETSOME
06-06-2003, 05:18 AM
Finally, dirt bike technology in a quad with no corners cut. I can't wait to throw my legs over yamaha's new quad!

sly400ex
06-06-2003, 05:22 AM
Are there any HP ratings on the motor yet????:confused2

GETSOME
06-06-2003, 05:31 AM
Can't find any HP numbers from a reliable sourse. I believe both the crf450 and the yz450f make between 45 and 48hp. The new yamaha quad uses the bottom end and gearing from the WR motorcycle for the electric start and all. The WR crank has a slightly shorter stroke than the yz450f rusulting in the 439cc displacement. Thats 11cc's less or 2.4% less cc... So...

100%-2.4% = 97.6%

48hp x 0.976 = 46.8hp

45hp x 0.976 = 43.9hp

That at least gives you a possible range of between 43 and 47hp.

airheadedduner
06-06-2003, 05:40 AM
I doubt it makes over 40hp. I remeber seeing someting on a pro built yzf quad and they were getting low to mid 40's with it. Stock, yammy probly corked it a little. I would bet you would see huge gains from just a pipe though. That thing probly won't need much as far as mods.

F-16Guy
06-06-2003, 06:54 AM
Yamaha also put a throttle stop and exhaust restrictor (or was it intake?) on the WR bike. I'd look for those on the quad.

JLanphear
06-06-2003, 07:00 AM
Take a closer look...I'm not sure of the lifespan of these engines...I've had similar ones in the past and they didn't last very long ;)

UglyMotha™
06-06-2003, 07:02 AM
those numbers would be for the dirtbike i'm willing to bet with it setting in the quad frame you only goin to see the motor putting either 38-40 horse down to the ground

UglyMotha™
06-06-2003, 07:03 AM
Originally posted by JLanphear
Take a closer look...I'm not sure of the lifespan of these engines...I've had similar ones in the past and they didn't last very long ;)


LMGDAO, now thats funny:p

06-06-2003, 07:04 AM
I know a guy that ain't right that'd prolly pay good monie for that. The pet store in town done cut him off.

Mxbubs
06-06-2003, 07:04 AM
That freaking hilarious.


I hope they put bearings around the cam so they cams arent riding in shim buckets like the rest of the YZ motors,and the old honda 350x motor.

UglyMotha™
06-06-2003, 07:05 AM
Originally posted by froggigginmama
I know a guy that ain't right that'd prolly pay good monie for that. The pet store in town done cut him off.



why does your buddy like to go gerbiling :huh

JLanphear
06-06-2003, 07:07 AM
Originally posted by froggigginmama
I know a guy that ain't right that'd prolly pay good monie for that. The pet store in town done cut him off.

LOL, now that's just sick :eek:

GETSOME
06-06-2003, 07:18 AM
that is one tough gerbil to be able to spin a DOHC motor!

infantry317
06-06-2003, 07:22 AM
ROTFLMFAO! :D

spliffy
06-06-2003, 07:45 AM
Tooooo funny with the gerbil pic LMFAO

RoadkillerRyan
06-06-2003, 07:50 AM
Originally posted by JLanphear
Take a closer look...I'm not sure of the lifespan of these engines...I've had similar ones in the past and they didn't last very long ;)


you get him outta there or im calling your mama

lil400exman
06-06-2003, 07:54 AM
i always thought they were high revving:confused2

F-16Guy
06-06-2003, 08:53 AM
I heard that Richard Geere is one of Yamaha's test riders.:eek2:

TheRedRebel17
06-06-2003, 09:04 AM
so thats what stinks in my motor :scary: