the 07 specs

YZ250F

www.yamaha-motor.com

YZF250 07

The YZ250F made its mark when it totally dominated the 2005 MX2 World Championship, taking the first three places overall, while Yamaha took the 2005 MX2 Manufacturers’ Championship. And with the Yamaha YZ250F occupying five out of the top seven overall positions in the 2005 MX2 World Championship, this free revving 250cc 4-stroke is rightly regarded by many as the machine against which all other bikes in the class should be judged.

With its combination of a rider-friendly power delivery, class-leading handling and lightweight steering, it is easy to see why the YZ250F has become one of the dominant bikes in the MX2 category.

For 2007 Yamaha’s engineers have focused their resources on achieving enhanced high rpm performance, together with even lighter handling qualities and stronger front braking power.

YZ250F ENGINE

Optimisation of the intake, exhaust and ignition systems

Although the basic architecture of this MXGP-winning 5-valve DOHC engine remains the same, a wide range of improvements to the intake, exhaust and ignition systems ensures even greater performance at high rpm and also in the over-rev range. These changes include a redesigned diffuser pipe, modified carburettor air vent passage, and new carburettor settings.

Revised engine mounting angle

The YZ250F is already renowned for its lightweight handling qualities, and to further enhance this reputation the 2007 model benefits from a revised engine mounting angle. In effect the engine has been rotated around the drive axis so that the cylinder is more upright. This change, together with the use of a range of new components including a lightweight engine guard ensures even lighter feeling handling.

Magnesium crankcase cover

Further weight savings are achieved with the use of a new magnesium crankcase cover which is 168g lighter than the previous design.

Lightweight oil tank

The dry sump engine features a separate oil tank positioned in front of the engine, and for 2007 a newly designed tank is fitted, featuring an additional internal partition which improves the oil/air separation. This has allowed our engineers to reduce the engine oil volume by 100cc, thereby saving weight.

2007 YZ250F Engine Technical Highlights

• 250cc 4-stroke liquid-cooled

• DOHC 5-valve

• Bore x stroke 77.0mm x 53.6mm

• Revised carburettor settings

• Optimised intake, exhaust and ignition settings

• Revised engine mounting angle

• Magnesium crankcase cover

• New oil tank with reduced volume

YZ250F CHASSIS

Please note that the YZ250F benefits from all of the same chassis improvements described in the ‘YZ450F Chassis’ section, and also features a number of YZ250F-specific changes as follows.

Repositioned head pipe

In order to accommodate the more upright engine angle, the YZ250F’s frame has been modified, and the head pipe is now slightly closer to the rider. The frame’s rigidity balance has also been modified by the use of a smaller diameter engine mounting bolt, while the engine mounting plates are also redesigned to allow for the new engine Page 10 of 18 mounting angle. The effect of these changes is to give a slightly more compact riding position, which makes for improved handling qualities, particularly when entering turns. New design front brake system

One of the primary aims for 2007 was to reduce weight, and this has been achieved by the use of a new compact front brake caliper. By reducing the piston size and redesigning the master cylinder and brake lever, we have been able to reduce overall weight by 228g, while at the same time increasing braking performance.

The YZ250F also features new wave type front and rear discs for 2007, and the discs fitted to the YZ250F are of a lighter design than those used on the larger YZ450F.

New lighter front fork outer tubes

The 48mm Kayaba front forks have also shed some weight for 2007, and now feature new outer tubes which are lighter, and also offer a revised rigidity balance for improved handling qualities.

New front fork axle bracket

In addition to the use of new fork outer tubes, the YZ250F also benefits from new front axle brackets. The new axle brackets offer a better balance, and complement the new front brake caliper to give progressive and controllable braking performance.

New shape engine guard

The shape and mounting position of the engine guard have been modified, resulting in a 75g weight saving, and this contributes to the lighter feeling handling of the 2007 YZ250F. Revised radiator hose layout

As well as the radiator changes outlined in the ‘YZ450F Chassis’ section., the YZ250F also benefits from a new hose layout which features lighter, more compact components while still offering the same coolant capacity.

New rear shock link

For 2007 the YZ250F is equipped with the same relay arm, bearings and spacer as fitted to the YZ250 2-stroke, resulting in both weight savings and optimised strength.

2007 YZ250F Chassis Technical Highlights

The following changes are specific to the YZ250F Chassis:

• Repositioned head pipe

• Redesigned lightweight front fork outer tubes

• New design front brake system

• New lightweight wave type discs

• New front fork axle bracket

• New shape engine guard

• Revised radiator hose layout

• New rear shock linkage

The following changes are shared with the YZ450F. Please refer to ‘YZ450F Chassis’ section for full details:

• New lightweight forged aluminium triple clamps

• New lightweight rear shock

• Range of stainless and lightweight parts

• New Pro Taper handlebars

So much for FI MXers in 2007 for any of the big 4.

100cc less oil? Is that an improvement? All in it looks like they shaved about a pound, but you better be damn sure you put in enough oil and you will probably have to change the oil after EVERY ride.

100cc less oil? Is that an improvement? All in it looks like they shaved about a pound, but you better be damn sure you put in enough oil and you will probably have to change the oil after EVERY ride.

if you read the spec careful enough, they put in a baffle into the oil tank and revised the oil line (my guess made of aluminum now). So that is where the lower oil level comes from.

you dont change your oil after every ride now?

sounds like some FANTASTIC updates to me!!

steve, where is the crankcase cover? :excuseme: I swear I can be so braindead sometimes.

Increased mass centralization and 2.5-pound weight reduction provides fantastic overall balance and performance.
2.5 pounds overall? wow that will make a huge difference.

Holy crap look at the color! It's white!

07yz250f_white_4_83d75eb0.jpg

It's got the gay european pecker extender on the silencer though :sigh:

steve, where is the crankcase cover? :excuseme: I swear I can be so braindead sometimes.

2.5 pounds overall? wow that will make a huge difference.

yeah, i'm still scratching my bald head trying to come up with that one.

do they mean the ignition cover or the clutch cover or both or neither? or it is something else all together?

bleach me white confused.

ugly color btw.

out of the 2.5lbs saved, i wonder how much of that is the 100cc less oil?

or are we using dry weight?

did rotating the motor make getting to the carb better or worse???

I would suspect it made getting to the carb easier but you know even that will be a relative comparison.

you dont like the white? I think it could push me into getting a couple fresh ones. The 04's have too many skid marks on the seat these days anyhow. :excuseme:

I sure hope that engine cover isnt a structural piece. Mag cracks so easily that it could force an even bigger skid plate killing the weight changes.

Holy crap look at the color! It's white!

07yz250f_white_4_83d75eb0.jpg

It's got the gay european pecker extender on the silencer though :sigh:

"pecker extender" :bonk: I kind of like the 06, um, endcap better...

The white color sure looks sweet though. :excuseme:

"Magnesium crankcase cover

Further weight savings are achieved with the use of a new magnesium crankcase cover which is 168g lighter than the previous design."

i guess my "source" had the name wrong.

however, the head cover was already thin and light. heck i thought it was already magnesium.

oh, and lighter guards just really means, these will bend easy.

"Magnesium crankcase cover

Further weight savings are achieved with the use of a new magnesium crankcase cover which is 168g lighter than the previous design."

i guess my "source" had the name wrong.

however, the head cover was already thin and light. heck i thought it was already magnesium.

oh, and lighter guards just really means, these will bend easy.

Yep, the 06 head cover is already magnesium. :excuseme:

http://www.yamaha-motor.com/sport/products/modelfeatures/12/1/features.aspx

oh, and lighter guards just really means, these will bend easy.

the positive spin would be they are much more compliant that last years. :excuseme:

Hmmm, I don't see anything too dramatic. Actually, I'm not too crazy about the reduction in oil capacity and flimsier guards. And I had a white 1990 YZ250...yeah, it looks cool at first, but man does it look like crap once it gets stained.

Hmmm, I don't see anything too dramatic. Actually, I'm not too crazy about the reduction in oil capacity and flimsier guards. And I had a white 1990 YZ250...yeah, it looks cool at first, but man does it look like crap once it gets stained.

Thank you for mentioning how the white gets ugly. I had a 92 WR200R and it looked great at first (LOVE the magenta and aqua blue, btw :excuseme: ), BUT exactly as you said, it would get stained with groad pretty easy.

If they wanted more retro colors, the WRs could be IT175 blue with yellow number backgrounds.

the wrs got better too aluminum frame pro taper big bars stock and a skid plate stock

for $100 more you can get the white "special version" new valves, new exhaust, trick brake rotars.new front brake. new carb and ignition. more top end and over rev. im not complaining :excuseme:

the white looks sweet!!!! is that color going to be in production or is it for show/demo purpose?

i also think the white looks sweet, but i bet it would look like crap pretty quickly. :bonk: i currently have the 06 model and love it.what i was wondering is with the changes they make every year to the bike why don't they put a good quality sprocket and chain on? :excuseme:

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