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03 yz450 compare to 05 06 07 08 09

27 posts in this topic

Hi ive got a yz450 03 moel a bit rough but had a few mods and to me it goes really well.Was just wondering power difference to the later model bikes as i was thinking about updating but i love the fact that i dont worry about dropping scratches all over it as i id when i bought my 426 new.I dont race just muck around with mates but lately been thinking bout getting into it. Thanx

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I don't know about power, but I'm pretty sure the yamaha 's were steel frame in '03. Just upgrading to the aluminum frame would be worth it. I imagine that the newer bikes have some more power.

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The 03 yz450f has the most abrupt power of any 450 ive heard of,puts about the same ponies but not mellowed out like the new 4 strokes

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I don't know about power, but I'm pretty sure the yamaha 's were steel frame in '03. Just upgrading to the aluminum frame would be worth it. I imagine that the newer bikes have some more power.

True. An 07 YZ450 frame will bolt right up to a 2003 engine and running gear, just need the 06-08 rear brake master cylinder, and possibly an exhaust adapter for the subframe mount.

Also, the 05 YZ's have the bigger suspensiong (48mm vs 46mm of the old) and in 06 they went to the SSS Kayaba units, very good stuff.

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So if i was on par with the other riders in skill level would i get chewed up by the newer bikes

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The 06-09 450's make more power they just have a milder timing curve to smooth the hit.

Definitely false, the 2003 or even 2004 for that matter would eat a 2007, 08, 09 stocker alive given all else are equal. The timing, exhaust , cam specs, and transmission ratios make for a more pure mx ride. Also the 2006 is faster than the 2007, which is faster than the 2008, which is the same essentially as the 09, relatively speaking.

Of course this is all for naught, because the suspension, handling (debatable), and weight all got better through the years.

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Definitely false, the 2003 or even 2004 for that matter would eat a 2007, 08, 09 stocker alive given all else are equal. The timing, exhaust , cam specs, and transmission ratios make for a more pure mx ride. Also the 2006 is faster than the 2007, which is faster than the 2008, which is the same essentially as the 09, relatively speaking.

Of course this is all for naught, because the suspension, handling (debatable), and weight all got better through the years.

NO:prof:Where's grey at:excuseme:

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NO:prof:Where's grey at:excuseme:

I do respect grayracer's opinion, but having raced an 03, an 06, 07, and 08 YZ450, I have come to that conclusion. If I was faster I would definitely try to find an 03 powerplant into my new chassis. The thing ripped.

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Thats just it though most think that the 03 has more power because of the midrange hit that it has. When really the 07 makes like 1.5-2 more hp. Dont get me wrong they are both yamahas which makes them both great bikes.

If you wanted the power curve of an 03 you could use an 03 cdi box

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Thats just it though most think that the 03 has more power because of the midrange hit that it has. When really the 07 makes like 1.5-2 more hp. Dont get me wrong they are both yamahas which makes them both great bikes.

If you wanted the power curve of an 03 you could use an 03 cdi box

Now you know you can't compare dyno pulls from different dynos, on different days, let alone pulls done years apart!!! I wish I would have kept all my bikes, I'd put money on the 03 nailing down the most HP over the curve, with all of them having roughly the same peak HP. The 03 had a nasty growl off the bottom and a big midrange hit.

My 08 feels very similiar to the 03 with the high cp piston and 06 cams, and the Dr. D pipe.

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I love my 03. I have ridden a friends 08 a few times and I do enjoy the chassis but the motors dont compare. I have been spoiled with the bottom end that my 03 makes. Right off the bottom it pulls like a freight train.

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03 is the slowest. The light flywheel and instant throttle response decieves you into thinking it has more power. The newer bikes have a more "electric" motor that smooths the hit and puts the power to the ground. I can not think of 1 instance where I would prefer the 03 motor.

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03 is the slowest. The light flywheel and instant throttle response decieves you into thinking it has more power. The newer bikes have a more "electric" motor that smooths the hit and puts the power to the ground. I can not think of 1 instance where I would prefer the 03 motor.

What do you race? I could think of many instances I'd prefer the 03 motor over the stock 08, the holeshot , tight corners with big jumps right out of the corners, freshly groomed tracks, sand tracks, hmmmm.....

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on the dirt you can´t compare the 06/03. you´ve got track conditions, rear wheel spining, etc.

i´ve got my 06 on sumo, and so a friend of mine on a 03, both stock, on the same gearing(more or less one tooth on the rear) and wee´ve tested somme starts, stoped or rolling and the 03 allways goes first( the 4 shift gearbox also helps allot)

on the track, its allot diferent, the smoother power delivery, frame, ryding position, and the gearing on my 06 5shifter leaves the 03 behind.

...but still ok for a weekend ride. the 03 has even missing a bit of the cilinder´s sleeve the sise of a pinky finger nail, the only way to make a YAMY burn oil:banana:

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Facts:

'03-'04 - 47/48 hp (stock)

'06 - 49/50 hp

'07 - 50/51 hp

'08 - 51/52 hp

JSanfillipo is right. When you actually run the bikes head to head on asphalt, the truth comes out. It's very even at low speeds, but the later bikes pull away on top.

9 riders out of 10 will turn faster laps on an '06-'09 than on an '03-'04, and will be able to do so for a longer period of time.

An '03-'05 yz450 engine will physically bolt in, but you will have to either construct an external oil tank or convert to wet sump. The later engines relocated the dry sump reservoir to the front of the crankcase, so the frame has no provision for carrying oil. With the current prices of '06 models, such field engineering may be interesting, but in the end, it's really not a practical approach.

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So if i was on par with the other riders in skill level would i get chewed up by the newer bikes
No. MX is at least 80% rider. You would have some disadvantages on your bike, and you'll get tired faster, and perhaps be less comfortable at speed, but a good rider can compete on the older bikes.

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The 4 speed transmission is cool on the older bikes, but some tracks, having an extra gear is nice

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Facts:

'03-'04 - 47/48 hp (stock)

'06 - 49/50 hp

'07 - 50/51 hp

'08 - 51/52 hp

JSanfillipo is right. When you actually run the bikes head to head on asphalt, the truth comes out. It's very even at low speeds, but the later bikes pull away on top.

9 riders out of 10 will turn faster laps on an '06-'09 than on an '03-'04, and will be able to do so for a longer period of time.

An '03-'05 yz450 engine will physically bolt in, but you will have to either construct an external oil tank or convert to wet sump. The later engines relocated the dry sump reservoir to the front of the crankcase, so the frame has no provision for carrying oil. With the current prices of '06 models, such field engineering may be interesting, but in the end, it's really not a practical approach.

Would you think that the dynos are even comparable since they were probably done years apart, and maybe even on different dynos? I'm not really concerned about wide open throttle, since I'm almost never there on the 450....I would wager to guess the 03 makes slightly more power where the 08 exhaust gives up a bunch of hp due to its restrictive design. Either way, my 03 is long gone, but I have some fond memories of shifting once per lap on that thing.

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