Wow looks like there is a king for the 400cc category and it is also a Giant slayer. Cant wait for them to come out or to see one on the MX track.

 

Hey is that rear wheel hp or is it at the crank?

 

Thats what I want to know!

 

Ok I read the story on the YFZ & they say that it should be about 40 HP stock at the rear wheels, So I'd guess that more HP should be easialy obtained by removing the airbox lid, taking out the baffle in the exhaust & rejetting (sounds like there's a lot of potintal bottled up in that engine). Like I said I just scanned through the story when I posted this & they said the MX bike had 45 HP so they guess the quad has 40HP.
They also said it has a new airbox design that allows you to remove the lid with the stock filter in. It's about time they fixed the air box!!
Also the rear swingarm is a new design with an easier chain adjustment.
The trans was beefed up from the YZ450F bike trans, looks like they don't want a repete of the 01 Raptor trans problems.

I just got my July issue in the mail a couple of weeks ago, but my Yamaha Dealer had the Aug issue on the shelf Friday.
Needless to say I'm not going to renew my subscription, I'll just pick it up at my dealer!!

This was just a preview, DW hadn't ridden it yet, there will be a full test in the Sept issue.

 

DW is totally lame. I don't believe anything they print. Just becasue its a Yamaha I bet it doesn't handle half as good as my EX. I'll wait to see how they do at the local races before I believe some homo's in California who produce that rag!

 

ummmm yeahhhh, I dont think your 1998 technology 400ex is going to even beable to compete against the 450! Are you fricken kidding me! are you actually saying that you think your 400ex will out handle the 2004 yfz450. Get a grip pal! I love honda too, but yamaha has got honda beat fair and square right now. (we'll just wait and see what honda comes out with)

 

Thanks for the update. Do you happen to know what was different on the moto version of the yfz? Did they race against anything else?

 

I don't beleive the atv rags anymore either but if that yamaha at under 350 pounds with the kickstart doesn't out handle your old ex then they better send them back to the factory. Saying half as good that's one stupid statement. I've read four of your eleven or so posts right now and two of them have been insulting to me and the other two have insulted someone else. Do you just like to jerk peoples chains, playing around or are you just a as..... buttehole?

 

Well said "mudslinger400z", I couldnt agree with you more!! Some people should just not be aloud to talk!

 

It uses the same head & intake cam as the MX bike but with a diffrent exhaust cam (from the WR450),
It has a slightly smaller bore & a larger crank pin than the YZ450F, it has higher compression than the bike (11.9:1)
They say the YZ450F's close ratio trans has been beefed up for quad use,
Also a quick change clutch cover is installed stock for easy clutch acess & the clutch has thicker steel plates.

The only thing they say they raced aginst was the Raptor & the YFZ won everywhere but top end.