Yamaha Ready to Win the Motocross Weight Wars

From www.motorcycledaily.com As expected, Yamaha will introduce aluminum-framed YZFs next year, in both 250cc and 450cc displacements. As a result, expect Yamaha to have the lightest four-stroke motocross bike in each class.

Just a couple of years ago, it was difficult to believe that four-stroke motocross bikes could be as light as the two-strokes they compete against. A 250cc four-stroke as light as a 125cc two-stroke motocrosser? No way, we thought. Not with those overhead cams and valves that the lower displacement two-stroke can do without.

Expect Yamaha's 2006 YZ250F to weigh roughly 211 lbs with fluids (empty gas tank). Still a bit heavier than the 125cc two-strokes, but only by a few pounds. Amazing.

Likewise, the YZ450F should leapfrog the Honda CRF450R to become the lightest bike in the class next year with its new aluminum frame.

Looks like someone is tired of seeing their marketshare being erased by the copycats. :D:naughty::naughty:

Are they just guessing? Who told them they're going to be lighter? And if they are, they may be lighter by a couple pounds, but will it actually feel lighter than a honda or suzuki?

Yeah even if it is a couple pounds lighter it will still have that same yamaha top heavy feel because of the 2 cams and 5 valves.

Better than an engine that eats valves and oil :naughty:

Better than an engine that eats valves and oil :naughty:

:D:naughty::D

Just nice to know that they are taking their time getting the aluminum frame dialed instead of just throwing something together like another manufacturer did when they released their aluminum frames.

The spy photos from Japan that I saw, looked like the engine cases were lower and more rearward.

Yamaha uses titanium (lighter weight but more strength than steel) valves, I doubt 5 of them weigh as much as 4 steel valves.

I don't think the alum frame is gonna make them feel a lot less top heavy because my 85XR250 feels lighter that an 04 YZ250F so i don't think that the top heaviness will go away with the alum frame.

Yeah, but it appears that the 06's will be wet-sump. I think having oil in the frame currently is part of yami's top heavy feel.

guys i wiegh like 155lbs and i can toss the 250f around

stop looking for somthing to complain about and learn to ride !

&%$#@! PLR i ride a 450 and weigh 150. we are not talking about it being hard to ride just talking about how it feels.

Yamaha definetly seems to be the hardest working 4-stroke manufacturer. They are always coming up with new concepts and ideas or at least try to improve them.

guys i wiegh like 155lbs and i can toss the 250f around

stop looking for somthing to complain about and learn to ride !

yes I agree I way 160 and ride the most top heavy bike of them all )02 wr 426). I have no problem keeping up w/ the smokers on a tight trail even w/ my 3.2 gal gas tank toped off. Did they say if the wr is going to get the alluminume treatment as well?

Yeah even if it is a couple pounds lighter it will still have that same yamaha top heavy feel because of the 2 cams and 5 valves.

Does this mean that the Yamaha is more top heavy than the Suzuki, because it has one more valve? :naughty: The Zuki is a DOHC motor too.

The motor is not the Yamaha's problem, for the top heaviness. The culprit is the frame design. It is very old school.

Better than an engine that eats valves and oil :naughty:

HA my old yamaha (2003 yzf 250) was nothing but a lemon i only had problems with it, i bought a honda this year (2004 crf 250) wow i havent had one problem yet and i think the honda handles 10000 times better and the suspension is 10000 times better and it seams faster yamaha is the only bike i would never buy again, well i only buy hondas now

Sorry to hear you were one of the few that had problems, every manufacture has their lemons, my 02 has been flawless. But there is living proof in the forums that honda's do have problems.

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