how do you tell the difference 250 450

how do you tell the difference between a yz250f and yz450f??? i know with 2 strokes the pipe and jug is bigger but how do you know if just looking at them???? a guy where i ride says hes on a yz250f but i think hes lieing how can i know what it is??? or even on like kx's, cr's and rm???:eek:

I always look for the rear tire size...a 450 will have a much wider tire on the back. I also listen to what the bike sounds like too. The 250f will rev higher and faster too. And if you can, pick it up! The 250f will be a lot lighter:thumbsup:

i dont know about the sound thing, to me the 250's and 450's sound the same mostly with pipes on them.. the tire thing. what if someone changed the tire size???? like any other way to know??? even with all brands?

The head and radiators are smaller on a 250F. For the Yamaha's I always look at the waterpump, they are very different looking on the outside. If it is an aluminum framed YZ then the 450 has the oil tank build into the engine with the dipstick in front of the cylinder and the 250F has an external oil tank in front of the engine (if it hasn't been removed).

i think he has a 03. i will have to look at pics of the water pumps so i can see whats he has.

In addition, the left side case cover for the ignition is different, the clutch cover is smaller on the 250F, and space between the head bolts is smaller on the 250F, giving the right side of the head an overall smaller appearance.

I think you sould look at the yamaha site, take 1 pic of each bike, compare them (they are A LOT different) and then look your fiend´s.

Just what I would do

i dont know bout the yzfs but on a crf/r the 450s header is different and of course the 250 is sporting dual mufflers. the upper engine mount is also different.

They have never looked "a lot different", although I know that's a relative term.

In 2000, when Doug Dubach was testing the prototype 250F, they took it to public races and ran it in the 250 class with the 400's and 426's and no one ever knew. "We took the stickers off and hid it by putting it in plain sight". :eek:

Here are pics of the waterpumps:

450:

064503.jpg

250F:

DSCF0577.jpg

it's pretty easy to tell for sure which one it is, they have the engine's size in "cc's" posted on the head. If I remember right it will be on the front of the head just below the header port. I'm surprised nobody pointed that out before.

That is true, when you can do that, but these other identifiers can be used to discriminate between the two at a distance, or in a photograph.

Exhaust pipe diameter is the easiest way, you can tell from 20' away which is which....

i dont know about the sound thing, to me the 250's and 450's sound the same mostly with pipes on them.. the tire thing. what if someone changed the tire size???? like any other way to know??? even with all brands?

they won't have a 110 rear on a 250f unless they ride muddy off-road races.

also, the motor is higher and wider on the 450 than the 250. but i'll admit, it takes a keen eye to tell the difference. the 450 does have a throatier sound to it.

also, the kick starter is a good hint. the 450f one is longer. im remember seeing that at the dealership when they were side by side..... im pretty sure

edit: okay maybe not

here compare these pics back to back and u can see every detail difference.

Yz450f

left: http://www.yamaha-motor.com/sport/products/modelimagelib/209/2/1/0/image.aspx

Right: http://www.yamaha-motor.com/sport/products/modelimagelib/209/1/1/0/image.aspx

yz250f

Left: http://www.yamaha-motor.com/sport/products/modelimagelib/12/2/1/0/image.aspx

Right: http://www.yamaha-motor.com/sport/products/modelimagelib/12/1/1/0/image.aspx

you can see the exhaust is different and the jug on the 250 is tilted forward where as the 450 is vertical. also the 450f has a raised portion between the cam covers, where as the 250 doesn't have that and instead as a depression between the head bolts

you can see the exhaust is different and the jug on the 250 is tilted forward where as the 450 is vertical.

The '05 and earlier 450 was also tilted forward.

they still look very close and i ment more if your our riding and see a guy on one. next if they were both parked next to each other it would be perty easy to tell but just one out on its own and a quick look it would be really hard to know for sure but you do have a 50 50 chance to guess right

The ignition covers are different and the 450 has a longer exhaust if stock

The easiest way for me to tell when riding is by listening to how high it revs. If it's a somewhat faster rider the 250f's are always revving really high. It's usaully pretty easy to hear the difference.

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