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TuningFork426

Old yz450 vs New yz450

18 posts in this topic

what is the difference in power between a 2003yz450 and a 2007yz450 I know that the 2007 powerband is way way smoother, but if both bikes had equal traction which one would win a drag? im guessing it would be pretty damn close with the 2007 a tiny bit ahead. Am i wrong? thnx:ride:

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i think the 03 would maybe win

maybe im dumb but i was draggin with one down a straight yesterday a few times and was pulling on him a touch of course there are many different variables at the track but i felt that my bike had more power....

however when it came to turning he was much better

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THere is nothing stock out there 450 that will out drag a 03 450 stock,,,,but there is nothing out there that will tire you out either like a 03 450 yami...

no comparison between a 03 and 07.....top fuel dragster vs smooth powerband and better handling

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My '06 and my '03, side by side on asphalt from a second gear rolling start, run side by side, like they were bolted together, up until I hit 4th on the '03. At that point, the '06 starts to pull. In the dirt, the '03 has a much harder time hooking up, and the '06 will beat it on that basis most of the time.

The numbers are close. A good '03 should make 47 hp stock, and you can add almost 1 hp for the FMF Ti4 system on mine. An '06 makes right at 50. As different as they each feel to ride, your butt dyno would predict a much different result, but it would be wrong. The '06-7 is sneaky fast.

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If you can go as fast on an '03 as on an '06, would would definitely be a better rider, yes.

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I have an 03/04/05/07 in my garage right now. The 03 with its light flywheel likes to spin the tire anytime you crack the throttle giving the illusion of more power. The 04 is everything the 03 is but better. All the mods people were doing to the 03 (heavier flywheel, clutch fix) are stock on the 04 without taking the fun out of it. The 05 is very electric with no hit but still every bit as fast as the 03/04. The 07 motor is very smooth on bottom to mid almost week feeling but has a nice mid to top rush. The five speed on the 07 smooths it out from the earlier years and is more versatile but unless I needed extremely low speed or high speeds I actually prefer the 4 speed. In a drag race with equal riders the finishing order would be 07,04,05,03 but they are all so close it is always going to be rider dependent.

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The 04 is everything the 03 is but better. (the) heavier flywheel...(was) stock on the 04
Yamaha did claim that the rotating mass had been increased on the '04, however, the flywheel, and every part of the crank except the rod and the rod bearing were the same in each of the '03-'05 models. The mellowing was done with the ignition curve.

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i'd say the 07 because it has more hp and another gear. when my dad had his 03 450 my uncle had a 426 that was a big bore to something and they were equal but then my uncle clicked it into 5th and walked away. the 03 has a hell of alot more grunt though.

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Yamaha did claim that the rotating mass had been increased on the '04, however, the flywheel, and every part of the crank except the rod and the rod bearing were the same in each of the '03-'05 models. The mellowing was done with the ignition curve.

My 04 went boom a few weeks back. I am going to part it ou but I think I will keep the CDI and see how it works on the 03.

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just unplug your TPS sensor heard that will add a lil extra ooompf i unplugged mine and am faster in a straight line considerably next to my buddy with the same exact bike as mine..

but i was under the impression that 06/07 were a bit slower the the 03-05 but i guess they are the same in a straight line... had me shocked but good to know...

now i wonder how the 08s compare since i have read user comments that they have lacking power

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I have an 03/04/05/07 in my garage right now. The 03 with its light flywheel likes to spin the tire anytime you crack the throttle giving the illusion of more power. The 04 is everything the 03 is but better. All the mods people were doing to the 03 (heavier flywheel, clutch fix) are stock on the 04 without taking the fun out of it. The 05 is very electric with no hit but still every bit as fast as the 03/04. The 07 motor is very smooth on bottom to mid almost week feeling but has a nice mid to top rush. The five speed on the 07 smooths it out from the earlier years and is more versatile but unless I needed extremely low speed or high speeds I actually prefer the 4 speed. In a drag race with equal riders the finishing order would be 07,04,05,03 but they are all so close it is always going to be rider dependent.

you are the 450 king:thumbsup:

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I have an 03/04/05/07 in my garage right now. The 03 with its light flywheel likes to spin the tire anytime you crack the throttle giving the illusion of more power. The 04 is everything the 03 is but better. All the mods people were doing to the 03 (heavier flywheel, clutch fix) are stock on the 04 without taking the fun out of it. The 05 is very electric with no hit but still every bit as fast as the 03/04. The 07 motor is very smooth on bottom to mid almost week feeling but has a nice mid to top rush. The five speed on the 07 smooths it out from the earlier years and is more versatile but unless I needed extremely low speed or high speeds I actually prefer the 4 speed. In a drag race with equal riders the finishing order would be 07,04,05,03 but they are all so close it is always going to be rider dependent.

Clutch fix? tell me more

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you are the 450 king:thumbsup:

Only the 04 and 07 are mine. The 03 is my brothers and the 05 is a friends that I do maintenance for. But I have time on all of them especially the 03.

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Clutch fix? tell me more

The 03 has a really crappy clutch stock. The simplest way is just to replace the clutch pack with the GYTR kit. It comes with a new actuation arm and clutch pack. If you are on a budget you can just replace certian parts but I don't recall which ones. I am sure if you do a search you could come up with the info.

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The 03 has a really crappy clutch stock. The simplest way is just to replace the clutch pack with the GYTR kit. It comes with a new actuation arm and clutch pack. If you are on a budget you can just replace certian parts but I don't recall which ones. I am sure if you do a search you could come up with the info.

its the 01/02 clutch plates and clutch boss kit

The GYTR kit is only 90.00 - 110.00

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