XB9R Headers on an XB12R??

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GW 04 XB12R

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Feb 9, 2010
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So I just bought a 2004 XB12R used from a dealership. It has an aftermarket can, with no brand name tag on it. It greatly resembles a carbon fiber Jardine, but I'm not positive. The bike also has a K&N air filter on it. It has definitely been remapped (maybe too much) because it smells very rich upon initial start-up, and has lots of power everywhere.

My concern is the header. The header on the XB12 is supposed to be 1.75" diameter, right? The header on my bike is the smaller 1.5". At first I was worried the bike was an XB9 with XB12 decals/badges, etc. But the frame is dark grey, and the VIN# says it's the 12. I am quite convinced it is the 12, but is there any way to tell from the motor itself? I know there is a number stamped right on the motor.

My question is this: Is it better, perhaps, to have the smaller diameter header on the 12 with the free-flowing can and filter? This will cause faster exhaust gases, etc. Or should the bike still have the thicker 1.75" header? Would I notice a difference? Thanks in advance.
 
That would make it run rich i have seen the two headers off and together in person. If it is a 12 the the 9 headers are way to small. You probably would notice a difference.
 
Hmmmm... Thanks for the input. I'll definitely have to figure out if it's the 12. If it's not I'm gonna be pretty mad. Any other inputs??
 
So I'm pretty much positive I have a Jardine, which is cool. And I read somewhere that the smaller header pipe may actually increase bottom end torque. The person who tried it said the top end power fell off a little from 5900rpm+. I don't know by how much.

In my case, if this is true, the smaller pipe is better. I'm not a racer, and spend most of the time under 5900rpm. Can anyone back this up or refute it?
 
just a smaller volume of spent gas; exiting faster than normal. like a venturi almost. increased pressure b/c of the 12 top end.
 
i have a 2004 xb12R and i purposely put on xb9 headers... there was a big change in the mid range... if you have a 12 with 9 headders you have nothing to worry about everything is just fine... although i do have my stock 12 headers layin in the shop if for some reason you would want to switch back to a 12 header...
 
well that's good news to hear, thanks man. like i said i do most of my riding low-mid rpm anyway...

if you were to sell your old headers, how much would you want for them? i don't mean to be a low-baller, but if you really had no use for them would you take $50 for them? just curious to make some dyno runs to compare. if not, not a big deal. i was a little concerned before, but not anymore, thanks.
 
id like to get at east $100 out of them... the 9 headers i got were off of ebay crashed for like 47 buck so headers really arnt that cheap lol... also both of my headers were taken off and polished on a buffing wheel so there super clean with a perfect gold color to them from the heat...
 
ok man, I understand. even $100 is a fair price on headers, no doubt. i just figured if you had them lying around and didn't care about em or w/e i'd buy em. if I needed them, i'd pay the $100. for now, i think i'll just stick with the xb9's until someone is looking to get rid of some 12's for cheap. thanks for the info though. i'm relieved to hear someone else with 9 headers on a 12 who actually likes it better.
 
lemme talk to my buddy, i believe he might be interested in putting a set of 9 headers on his 12 as well if so maybe we could do a lil swaparoo... ill ask him
 
You should definitely see an improvement in torque with smaller primaries on an XB12 due to better cylinder scavenging at lower RPMs, you may even see better fuel economy. I have found my 12 pulls better wheelies from low end grunt than it does winding it up. With the longer stroke of the 12 there really is no reason to spin the thing up to redline, you may as well make the most of the grunt with the smaller pipe and be happy. Even the XBRR uses the shorter strok XB9 motor for high revving horsepower.
 
Hmmm thanks for the advice. I think I will just keep the smaller pipe on. After all this discussion it seems more suited for my riding style. I'm not a racer, I love the way the thing sounds just cruising around. And I also love the fact that if I need power I don't have to downshift, just gas it and the power is there at any rpm over ~2000.

The bigger pipe looks cooler when comparing side-by-side, but the smaller one doesn't look out of place by itself. I also plan on putting some black wrap on it to cover up some scratches (oops) and to further improve exhaust gas speed. Plus I think the black will go better than gold.

I do have one question though: Those who said they noticed more torque and bottom end power, do you have an aftermarket exhaust and air filter? How would this change the results? I would think it could only help, right?

--- black_xb12r --- thanks for the offer to ask your buddy, but for now I think I'm all set. If I change my mind in the future, though, I'll let you know.
 
hey no problem man... if i were you id keep the 9 header on too! lol i think youd actually be feel a disappointment by going to the 12 headers lol the 9's ake it pull alot better...
 
G W hold up I had 9's on....not on purpose the mechanic put the wrong ones on.they cracked from the pressure. top end was increased but they cracked my headers and my d&d exhaust. put my old scratched headers on damn it gained more power then before.
 
hmmm that's weird. well i think if the 9 header cracks for come odd reason, maybe i'll buy a 12 to replace it. but are you sure thats the reason it cracked? a common factor are mis-torqued header bolts. it's possible the mechanic screwed that up, especially if he didnt even know what header to put on.
 

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