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Brothers 426 KILLS my new 450 ????

30 posts in this topic

I bought a new WR450 so my brother found a used 01 (I think) YZF426 for a real good price and bought it and that 426 absolutely smokes my 450. Don't know anything about the 426 other than it's pretty loud and looks like it has some sort of aftermarket pipe on it. But it's on a whole different level, in fact it's sick fast. Mine has the free mods done by the dealer and it runs ok but nothing like this 426. I finally got mine out on a big wide dirt road and it has a little stumble right after mid range and then the top end is really flat, just quits pulling. It just turned 120 miles. Do they need some more break in or does it sound like the jetting is a little lean? I ride at about 5000'. Actually I'm glad mine doesn't run as hard as that 426 because it's just plain scary.

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Mate read my thread titled 'WOW' outa the crate these bikes suck, but with a little work its amazing what they become!!!!

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Open up the jetting d-base sticky at the top of this forum. There's all you need there to get your bike's jetting dialed in.

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My uncle has a 426, mods done with a full FMF system. It runs very very well. However, it does not hold a candle to my 450. The 450 just has so much more power. I would check out your bike and make sure everything is OK.

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a YZ426 (even with a stock YZ pipe) will feel like it is 10 times faster than a stock WR450. The YZ timed 426 engine was known for it wicked powerband. One thing I miss about installing that YZ450 cam. Do all the mods to the 450 and it'll be quicker than the 426, but it'll never feel as fast.

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all the other users who have replied have a sommon sentiment. set your bike up to suit your riding style and power requirements and you'll be laughing. if you can throw in into corners with ease and power on early you'll have the 426 for breakfast! there are many considerations that you need to make yourself aware of, jetting and suspension set-up are just to name two of them.

if it makes you feel any better, i have seen with my own eyes a jetted '02 yzf426 that was more than capable of throwing stones all over an '04 525 ktm. and i shit you not, even the pipe was standard yzf!!

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if you can throw in into corners with ease and power on early you'll have the 426 for breakfast! there are many considerations that you need to make yourself aware of, jetting and suspension set-up are just to name two of them.

if it makes you feel any better, i have seen with my own eyes a jetted '02 yzf426 that was more than capable of throwing stones all over an '04 525 ktm. and i shit you not, even the pipe was standard yzf!!

Keep in mind we are comparing apples and oranges here. I doubt regardless of the Mods (with 2 riders at the same level) that a WR450 will have a 426 for breakfast on the MX track. If you were talking woods, I would agree that riding a stock 426 in the woods can be a handful and the WR has the upper hand. As far as your KTM comment. You are absolutely correct! I can say that in my last MX race, I lined my stock 2000 426 up right next to a guy on a KTM 525 (The guy is a much better rider than I am) and I absolute ate his lunch and everyone Else's! Also to note the level of riders I was racing with, I still finished last! These guys were all out of my league (I am Vet C rider in the woods and a beginner in MX - These guys were all MX B-Riders) but I still got the holeshot on all of the 250 2-Strokes, 450 four-strokes and the KTM.

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i have to question just what free mods your dealer did. somethings not right. at the very least he has to change the throttle screw to a YZ screw, cut the grey wire, insert out of the air intake (top of the air box), and pull the plug out of the exhaust. will it run with a YZ? maybe, maybe not. but it should at least give it a run.

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I seen a dyno chart in one of the dirt rags :applause: and the 02 YZ426 had more peak HP than a 05 YZ450 :) My old YZ timed 400 felt faster than my 05 450..I have a YZ cam now, just waiting for a need to re-shim.. :eek:

As stated before...do all the mods and re-jet, pmb exhaust insert or aftermarket silencer and your bike will wake-up..still may not feel as fast, but will be faster..

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Actually he's a way better rider but that's not it. We drag raced side by side and I rode his bike.......it's the bike......way more power. My dealer said they did the grey wire, throttle stop screw thingy, and airbox mod to mine. Left the stock baffle in. I did notice his 426 has some weird numbers scratched on the back side of the cylinder. ???

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A contributing factor is that the 426 is nice and loose and completely broken in, while the 450 is essentially a brand new, tight bike.

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Pull the baffle and go up on your main jet. That baffle really robs the power and responce. Once you do that and get your jetting dialed in, you should be able to outpull pretty much any mx bike on the top-end.

I beat mikes 03cr450f on my 01 426, all it has is all the freemods and a jd jetting set-up. I even have it wr timed still :applause:

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I didnt realize that the 426 was a YZ. My uncles 426 is a WR. I should have read the intial post a little more closely. :p Therefore you can take what I said and throw it right out the damn window. :applause::):eek::p

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your jetting is off...

Order yourself a bigger pilot jet and several main jets and start experimenting with it. The 450 is a lot of things, but flat on top isn't one of them. I wouldn't run it hard until you get it jetted right. It will run hotter and with less power until you do.

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I seen a dyno chart in one of the dirt rags :applause: and the 02 YZ426 had more peak HP than a 05 YZ450 :p My old YZ timed 400 felt faster than my 05 450..I have a YZ cam now, just waiting for a need to re-shim.. :eek:

Sorry, I find that EXTREMELY hard to believe... :) If I am wrong.. can you come set up my WR? :p

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Actually he's a way better rider but that's not it. We drag raced side by side and I rode his bike.......it's the bike......way more power. My dealer said they did the grey wire, throttle stop screw thingy, and airbox mod to mine. Left the stock baffle in. I did notice his 426 has some weird numbers scratched on the back side of the cylinder. ???

Your dealer did part of the free mods. Unless you do all the mods, you aren't going to benefit. Your exhaust is choked down big time. I'd assume they didn't rejet your bike either.

Regardless, you'll have a hard time in a drag race against that YZ. It's got a close ratio transmission, it's lighter, the engine is YZ timed, etc.

My WR426 that was completely open with YZ timing and an FMF Q was fast and I had no problem beating KTM 525's doing a Marcus Moberg impersonation.

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...and I had no problem beating KTM 525's doing a Marcus Moberg impersonation.

:):eek::p

Actually, an MM impression is only talking and asking about the race, not actually doing it. :applause:

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