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btray

04 yzf 450 hp rating

21 posts in this topic

My brother-in-law and I just bought a couple of 04's and wondered what the hp rating is for that year. We are old 2-stroke guys (55) and are testing the waters. So far we are having fun...bought a flywheel wieght to see if that makes any difference. Thanks Bill

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I don't know what they were rated at, but I've seen good dyno sheets that show about 47.5 for the '04. That's jetted, but otherwise stock.

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Thanks for your reply...I highly respect your opinion...as I have watched you respond to many posts and forums... your technical and wit are always enjoyable

Bill

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.bought a flywheel wieght to see if that makes any difference. Thanks Bill

Keep us posted on that. I'm considering a FWW for my '04, too.

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I have the 04' also....

Adding a Dr. D 6 ounce heavier flywheel, definitely improves riding off-road, as well as helping on MX tracks. On tight, twisty, uphill trails, the stock flywheel will tend to not have enough inertia to keep the bike chugging over well, which results in occasional stalling. The additional weight provides better rear tire hookup, as well as making trail riding more friendly.

Two of the best things I did to improve off-road riding were the Dr. D flywheel, and a Dr. D slip-on exhaust. This thing climbs like a Mountain Goat now.

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My brother-in-law and I just bought a couple of 04's and wondered what the hp rating is for that year. We are old 2-stroke guys (55) and are testing the waters. So far we are having fun...bought a flywheel wieght to see if that makes any difference. Thanks Bill

47/48 stock.....but my advice to you..w/o your brother n law knowing...buy a bigbore kit have it installed.....then you will have more hp than him....:applause: :applause: :applause:

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Like that idea, but it's got plenty of power...the both of us reck so often that we between the two of us are running out of bones that havent been broken. So far me both collar bones and a shoulder blade...brused hip and back on two different ocassions...he has broken his jaw, ankle, rist, torn his rotator cuff. He's almost back up to his best speed and I'm about 70%, but we're having fun reliving our late 70 and early 80's motocross years. My son who is 30 got us back into it and we're having a blast at our own track on about ten acres of the twenty. We just need lots of prayer.

Thanks for all the info and comments...enjoy talking to you guys.

Bill

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Will let you know how the flywheel weight works after this weekend...thanks for your interest.\

Bill

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04, hi comp piston, leo vince pipe, ported/gas flowed head, jetted, never had it dyno'd but it eat my mates 07 510 husky think there 56 stock...

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Do you think a 13oz is too much?

I ride both Tracks and Trails, and I use the 6 0z. heavier model, from Dr. D.

I like the 6 oz. for doing both the track or trails, but If you're going to primarily ride on trails, than I'd go with an 8 oz. heavier model.

I've heard 10 ounces is pretty good also. I think the 13oz. model might tame things down a little too much, but I can't say from actual experience. I'd get a Dr. D model, since they allow you to exchange different weight flywheels if you like, at any time.

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If you've never tried the 8 oz Dr.D , you should. This is the flywheel the '03-'04 should have come with in the first place.

Whenever you are comparing flywheel weights, keep in mind that they are of two basic types, and that these two types cannot be directly compared on an ounce-per-ounce basis. The bolt-on weights require drilling and tapping, fasteners that can potentially loosen, and can be installed improperly (although it's not that hard to do it right), and can cause a balancing problem. Welded on weights are permanently added to the flywheel, can't come off, and are balanced after installation. Also, because all of the weight of a weld-on is located at the edge of the flywheel, an 8 oz welded weight can add more inertia mass than many of the 10 oz or heavier bolt-ons.

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Good point regarding using an 8 ounce weight; I've only used the 6 oz. model, and I'm very pleased with it, but maybe sometime I'll exchange for the 8 oz.

I got my 6 oz pretty cheap off of #bay, so that's why I went with the 6 oz.

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That's the cool thing about the Dr.D flywheels. You just swap them. He doesn't care at all whether you were the original purchaser or not, or how many times you switch (although I'm sure there's a limit at some point).

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If you've never tried the 8 oz Dr.D , you should. This is the flywheel the '03-'04 should have come with in the first place.
I've been considering a flywheel weight for my '04. I use it primarily for "fun" MX but am going to start doing some open trails and semi-desert stuff soon (see Riding Areas Forum, TX, Canadian River).

I like your points on the weld-on weight. You think if I go with the 8 oz Dr. D that I'll like it and never want to remove it? If you say "Yes, absolutely", I'll trust your word.

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i have an 03 yz450 making 63hp but its not stock

theres no way your bike makes 63 hp the pros bike only make like 55

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theres no way your bike makes 63 hp the pros bike only make like 55
It's a flat tracker. The mods and cams used in that venue are another notch up from the most ferocious MX'er you've ever seen. Ron Hamp, however, a builder of more than one top 5 National Championship ride, calls it a major accomplishment to have finally produced a 62 HP YZ450, the head being a limiting factor. So, I think 63 is a little bit of a stretch, but it could just be differences in dynos. Either way, it's more believable than you think.

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Gray racer is right on the money i beleive the 04s actully produced a little more hp than the later models. the last good dyno that i did was on a 06 450 with 1 hour of riding on it and it produced 46.6 hp.i will no if 63 hp is possible by next week im testing a new intake cam .when i mean possible im also trying to maintaine a good curve thers no dought if you wanted to see 63 or 64 hp from won of these bikes it can be done @ a sacrifice in mid range power i have done it playing with 250 hondas the power was going strait up @ 13000 rpm to the limiter but the mid range sucked .

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63 hp...I read an article that Carmicheals Honda back in 04-05 season made 60...I figure thats pretty good for a Honda...63 is believable for yamer...back on subject, I have the SFB flywheel that goes on over the existing flywheel by taking the nut off and replacing with theirs...the 90z doesnt require the cover they make but the 13oz does...I'm inclined to start with the 13 and and see if it fits my riding style while I get use to the bike then go to the 9oz. As far as welding one on why would mounting like SFD be a problem if you used locktite?

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