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rbn14

This is how fast your 2007 WR450 will go...

41 posts in this topic

...well sort of...

wrGearing.jpg

This is based soley on gearing and rpm. Assuming there are no drivetrain losses, wind resistance, perfect traction, no rider, that you can actually get to the rev limiter in 5th, etc... If I had to guess I would say at-least 20% loss due to all these factors, meaning 91.2mph (max speed = 114mph in figure) top speed. I would guess that is still an over-estimate.

I used 11500 rpm as the rpm ceiling. I personally, have only seen 82-84 with stock gearing and free mods. And that is when holding it wide open for an extended period of time. That would equate to 26% - 28% loss due to said contributing factors...

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Well said, and i love the chart. Where did you find it.:smirk:

I made it real quick. I thought the post about how fast a wr450 will go was getting ridiculous so I thought I would attempt to clarify things a little. If anyone is interested I guess I could clean up the Excel file a bit an post it so you can see how changing sprockets will change things.

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I've seen 92 w/stock gearing, free mods, AIS removal kit, on flat hard packed dirt road.
Had mine at 97 indicated before letting off. Front end gets a little unstable.

Your both NUTS...............any little ditch and youd be road kill.......I LOVE speeed (the legal kind) and that is fast.......not sure my 08 would do those speeds even with all the mods I've done.......

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Your both NUTS...............any little ditch and youd be road kill.......I LOVE speeed (the legal kind) and that is fast.......not sure my 08 would do those speeds even with all the mods I've done.......

I've been twice that on the pavement. :smirk: (Controlled conditions of course).

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I've seen 92 w/stock gearing, free mods, AIS removal kit, on flat hard packed dirt road.

i've done all the mods to mine and have only seen 84 and that was on pavement...

Had mine at 97 indicated before letting off. Front end gets a little unstable.

you just had to out do esbotto huh?:smirk:

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I've now had my 07 that is running 15/48 gearing up to 115 mph and it was still pulling when I let off but I was running out of fire road.so what is the max with 15/48 ?

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I've now had my 07 that is running 15/48 gearing up to 115 mph and it was still pulling when I let off but I was running out of fire road.so what is the max with 15/48 ?

man... i need that gearing! i already go through the whoops at Dumont in 5th gear pinned!

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I too have 15/48 gearing, much better on the road as the rpm's are lowered for cruising, nice to see the chart though

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man... i need that gearing! i already go through the whoops at Dumont in 5th gear pinned!

just pop on a 15 front it does most of it , but you will lose a bit slow speed for the tech stuff.

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I've now had my 07 that is running 15/48 gearing up to 115 mph and it was still pulling when I let off but I was running out of fire road.so what is the max with 15/48 ?

This sounds like my brother last year during Vegas2Reno. He gets off the bike and tells me "your bike is running great, I was doing 125 mph accross the dry lake beds and it was still pulling." We were running 15/45 gearing and did get the bike up to 102 mph but he hit the computer before the race started and changed it to KPH. :smirk: My brother is fast... Jeff S

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All of this is subject to factors varying for each rider and bike. The losses will vary depending on weight, resistance, bearing lubrication, chain lubrication/tension, wheel balance, jetting, exhaust , traction and the list goes on. If you can spin the motor up and get positive traction the gearing spreadsheet states the facts. You could gear it to 15-35 if you wanted but the motor probably wouldn't make enough power to overcome the losses and spin on up. That said, these bikes are fast. If your bike only runs 70 then you can do more. The average seems to be 85-95 stock gearing. I get over 90 on mine on the street with D606's. I think 85 in the dirt is respectable and probably accurate. Anybody running 85 who doesn't wanna concede to this...line 'em up...3-2-1 blast off:eek:

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This sounds like my brother last year during Vegas2Reno. He gets off the bike and tells me "your bike is running great, I was doing 125 mph accross the dry lake beds and it was still pulling." We were running 15/45 gearing and did get the bike up to 102 mph but he hit the computer before the race started and changed it to KPH. :smirk: My brother is fast... Jeff S

115 mph that was a gps speed . I was testing how close the stock speedo was . I was losing faith in the stock unit so I tested it was reading 121 at the same time as the gps was reading 115. One more reason to rip that pos off my bike , I was going to reset the tire size to get the speed reading right on but I bumped the wrong button and lost my mileage again . so I ripped it off . and here's the one I just put on . while I'm setting mine up to run a bit of super moto.

DSC00899.jpg

DSC00898.jpg

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I've had my '06 WR450F up to 93 mph. Stock gearing, gray wire removed,uncorked exhaust , YZ throttle stop, AIS kit not yet installed either at that time.

I had to see what it would do, at least a half dozen times! :smirk:

Mark

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does the wr really do 40 in 1st gear?

Not a chance. That was part of my point for starting this... there is a lot of bs flyin around...

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When looking a speed in terms of gearing, wind resistance and other factors don't play into this. I can peg my bike in 1st gear, and there is no way it's doing 40mph. Gearing is how fast your bike could go, if all things were optimal. You don't factor in drive train loss when looking at gearing. You only do that with horsepower /torque.

I think your math is wrong someplace.

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When looking a speed in terms of gearing, wind resistance and other factors don't play into this. I can peg my bike in 1st gear, and there is no way it's doing 40mph. Gearing is how fast your bike could go, if all things were optimal. You don't factor in drive train loss when looking at gearing. You only do that with horsepower /torque.

I think your math is wrong someplace.

I mentioned all that in the original post (and you are absolutely right). As far as my math goes, I will give it a double check this afternoon, I threw that together pretty quick and dirty, although I kind of doubt it is wrong.:smirk:

Also, if someone with a tach can confirm the rev limit, it would help a little.

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