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Discussion Starter #1
ok I bought a 2005 450r and a 2007 450er a couple of weeks ago. I adjusted the valves on both of them and changed the oil 1st thing. the 05 has a dynojet kit , no airbox lid , k&n filter, 50 pilot and a full rossier exhaust system. as far as I know that's all but cant confirm if anything else is done to the motor . the 07 has a modified lid, ncvq needle on 3rd clip , 162 main, 45 pilot , 55 leak , k&n filter and slip on hmf silencer . both bikes run good but the 05 pulls way harder from mid up and the 07 has more grunt on the low end. in a actual drag the 05 will take my 07. my question is why ? is it the rossier exhaust or am I missing something somewhere
 

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Yes more then likely the exhaust is making that much of an improvement. Dasa, Rossier, Monster, and Curtis Sparks exhaust systems are just really well designed exhaust systems. The 05 is breathing way more then the 07 can right now because the 07 stock header is super small. That's why if you talk to a lot of Professional Builders they will strait up tell you if you wanna make power... get a good brand. That's because they're real tested during designing. A Pro builder will never tell you to just get a slip on unless you just want a good sounding bike really slips on mufflers are good for is making some noise.

Now if you put a Rossier or Dasa exhaust on the 07 one too it would be a bit quicker and much snappier throttle response, at that point will probably walk all over the 05 with identical mods.
 

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Discussion Starter #6
And I have one of those tacks that wrap around the spark plug wires and it’s only showing a max rpm of 9380, that’s not even what it says this bike revs out to in the manual
 

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Yes that header is defiantly stock I for sure would upgrade the exhaust system...

As for the air box lid off (or cut) with a good Uni Filte with a good exhaust will breath just good enough.

That quad should rev to 9850... The 2004 and 05's rev to 9500. I'm gonna go with It might just be the Tach is not reading 100% on the spot. Especially if it's a cheap one.
 

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Are you hitting the rev limit when your tach says 9380? Or just out of power and need to shift? With most mild builds you run out of power long before 9380

If you can find a HRC header for your 07 that's all you need till you have much more work done. There is an old exhaust shootout where the HRC/HMF combo made less then 2hp less then the most expensive full systems on a 50ish hp build. Till you step up to a ported head, bored FCR, stage 3 or web cam you just won't see much hp from a "better" exhaust.

What gearing and tires are the two quads running, it's nothing to gain 3-4 quad lengths with the right gearing combo
 

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Discussion Starter #10
Stock sprockets on both. It sounds like it hit the rev limiter but I was gonna try a 160 jet in the 07 to see if it’s maybe running a little rich for pretty much being stock
 

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Pull the lid, the 04/05 HRC kit came with the cut lid and on the dyno it didn't effect the A/F reading very much but honda never intended the 06+ to run the modified lids. (Keep in mind they already had them in stock for the 04/05's) so why "remove" the lid on the 06+ HRC kit? To me there must be a reason. With the different intake tube the lid might have a different effect on the 07, and without it and the jetting you have you basically have the HRC kit minus the cam.

Were both bikes running stock cams?

Is the green wire cut on the 07? It does more then just raise the rev limit, it changes the timing a little
 

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Discussion Starter #14
I called rossier and they said that pipe would give that 05 a 10 hp gain , not sure if that’s true but that’s what they said
 

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Did they offer to sell you some ocean front property in arizona too? No exhaust I. The world will give a otherwise stock 450 5hp not to mention 10

How the give you those numbers is by supporting parts, you swap to their exhaust from bone stock, so now you need to rejet and remove the lid (more air out needs more air in) so did you gain 5 from the exhaust? Or did you gain 5 from more air more fuel AND their exhaust?


Then you have your head ported with plus 1 valves, add a high comp big bore, FCI intake 43.5mm bored FCR, green wire mod, web 208/921 cam, port match you intake manifold.
Now you dyno that with a bone stock exhaust and adjust the jets to proper A/F and get a number
Now bolt on their exhaust and dyno it again with adjusted jetting and get a new number, sure it's likely to be 10hp higher

So did you gain 10 from just their exhaust? After all it was the only change made besides proper jetting for each
Or did their exhaust allow the rest of your parts to do their jobs?
 

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And I tried finding a hrc head pipe, they aren’t any I seen
That sucks, back in the day they were everywhere
Measure yours, if it's 1.5" it's stock if it's 1.625 it's a HRC

Search the dyno section for pipe shootouts, if I remember right it was Mr.bulldog that did the hrc vs others test
 

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It stays 1.5"
A small header will make more power at low rpm's and less at high rpm's while just the opposite for large dia headers.

That part of the reason for stepped headers, at low rpm's the smaller section helps with bottom end power and as it steps up you aid all the rpm's. Also it creates a scavenging effect, as the exhaust gas leaves a smaller section and enters a larger section the pressure drops which helps "pull" the exhaust gas from the smaller section.

If you ran a 2" header at the head you would have a gutless wonder of a motor till about 9000 rpm's
 
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