It's on the features and benefits page.

Kiwi Craig, did you quote that from the Yamaha website? TIA

 

I agree 100%.

cc's don't always mean power. Go ride the bike.

 

kiwicraig,

i dont think the yamaha tech is right the spces of the two bike motors are the same and the quad is different so how can it be between the two?

 

i read that 2. it will be similar. it is not detuned that much at all.
10cc doesn't mean that much and the compresion is pretty close....

 

I agree more cc's don't always mean you've got the more powerful bike. This quad sure hasn't been detuned as much as some of the others have. Like you said 10cc's ain't very much.

 

I was riding with a guy I met out here in the desert, he was on a "98 YZ400f. The dude was haulin' azz, I was on my 2000 KX250 and his ride was Faaaasssttt! Not to mention he is in his 20's, hasn't been injured as much as me and at a young tender age his ********* are much larger than mine.[img]i/expressions/face-icon-small-blush.gif[/img] The point is, the four stroke Yamaha's are very potent and I don't think this one is any different. It's smaller displacement I'm sure is to allow it to be eligible for certain racing classes. Make no mistakes, this quad is smoking.

 

Was part of a every informative article on the ATVscene website last Friday.............but hmmmmmm, now its been pulled or I just can't find it, but geee, it WAS their headline story. Maybe YAmaha didn't want all the details to be laid out like it was but awesome tech.

scrambler123: you need to school up on your yamaha 400 /426/450 YZ and WR engines bud.

Specs: the WR and YZ engines are different; basically as follows:
WR has a milder exhaust cam than the YZ, both have the same intake cam. WR has electric start, and the 5 speed as per the older YZ 426. The 450 YZ went to a 4 speed. There are apparently differences between the ignition on the WR(retarded more at low rpm) and the YZ which gives the YZ more low end bite.

the quad engine is kinda in between due to the minutely different stroke and different piston, basically the quad engine is a WR setup with a beefed up gearbox.

Stuff is interchangeable between all these engines as the head casings are identical. The YZ exh cam bolts straight into the WR and is a very popular mod in NZ. Disconnecting the TPS grey wire on the WR apparently gives em more low end wick like the YZ but could be hard on the electric starter, Quad has the same TPS carb deal. All of them use the same basic carb body: 39mm FCR and the same head.

Yamaha will choke up the intake and exhaust from the factory to minimise RPMS and keep the warranty claims to a minimum whilst probably still delivering 38 - 40 hp.

Pretty simple to fix, through the airbox lid, fit a decent exhaust can and rejet. Yamaha tech article claimed an instant 20% increase in HP.

Want more HP add the 13:1 piston and YZ exh cam, want EVEN MORE, add hot cams intake and exhaust cams and hold on.............

I'm sure every engine builder in the business is already got stroker big bores on the bench for this thing.............

 

I hear ya - were gonna need some serious work wo keep up if all this is what it seems to be - but hey thats all cool we will all be riding more powerful quads in a couple of years (or less) to keep it from happening!

PS. the ys went to 4 gears because there was enought torque to do so...is that not what we all want? ft/lbs x rpm/5252=> LMAO250R (i hope, lol)