Standard vs Aftermarket

9 replies to this topic
  • Dicko187

Posted January 21, 2009 - 12:10 AM


I'm contemplating buying a headerpipe for my '07 450.
Only problem is, I'm torn between the header pipe Pro-Circuit offers or the Standard '09 450 'powerbomb' header.
So, does anyone have any advice as to what way to go with it?
I'm leaning towards the standard one as I know it'll give me a more instant hit off the bottom of the power, plus, it comes with a pipe gaurd on it and i wont have to buy a new one :thumbsup:

  • Kasjok

Posted January 21, 2009 - 12:25 AM


I would go with the stock header. Unless there`s a large difference in cost.

  • grayracer513

Posted January 21, 2009 - 07:13 AM


The "bomb" types should give you a wider, flatter power curve with about the same peak, and that, IMO, is more useful than the alternative. Plus you have it already.

  • sacfelix

Posted January 21, 2009 - 04:11 PM


How much of a difference would a megabomb be compared to the stock header or even the power bomb?

  • Dicko187

Posted January 22, 2009 - 12:41 AM


The "bomb" types should give you a wider, flatter power curve with about the same peak, and that, IMO, is more useful than the alternative. Plus you have it already.

nah, i'm talking about buying a header off an '09 450 to put onto my '07.

was just wondering which would be better suited for a bit more bottom to mid

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  • grayracer513

Posted January 22, 2009 - 07:06 AM


You need to check the header diameter to begin with.

  • Dicko187

Posted January 22, 2009 - 06:14 PM


the '09 header will fit onto my '07.

i've already checked all this stuff out, asked around and what not...I was just curious as to what others thought of the idea.

I called into my dealer today and was looking at it again, I was very tempted to tell him I'll take the bike...

  • WR450FGreg

Posted January 23, 2009 - 11:18 AM



You need to check the header diameter to begin with.

The '07 header diam varies from 43 to 46mm.
The '09 "powerbomb" header is smaller, but I can't recall how much smaller at the moment.

I have fitted an '09 Powerbomb header to my '08 WR450F and I'm about to take it for it's first run today.
(Prior to this it had the '07 YZ450F header fitted.)
If it's of any interest I can give you my opinion of it's seat-of-the-pants performance tonight if you like.


  • Dicko187

Posted January 23, 2009 - 02:31 PM


I'd really appreciate that Greg, Thanks.

the diameter is different in alot of places, BUT, they're still the same diameter at the 2 places they need to be, at the
clyinder and where the muffler slips on so that's all i was worried about, i did actually measure both on my 450 and the one in the shop but i can't even slightly remember the sizes :banana:

  • WR450FGreg

Posted January 24, 2009 - 05:06 PM


Ok, I took the WR450F fitted with the '09 YZ450F "powerbomb" header for a run yesterday.

Bear in mind that I hadn't re-jetted it after removing the '07 YZ450F straight header, I simply took one off and put the other one on.

To be honest I couldn't really feel any difference in performance at all. (I'm not a slow rider by any means BTW!)
The only difference was a tendency for the bike to stall a bit easier than before, but this is no doubt due to a combination of the lack of jetting adjustment, and the unusually high (for riding) ambient temperature, which was around 32 degrees celcius (say 90 degrees F).

If it was me I'd be sticking with the one you have Dicko, unless of course it is damaged or something.

I'm now in two minds as to which header to keep on my bike. The "powerbomb" looks more impressive at least. That could be the only reason I'd leave it on the bike!

Maybe re-jetting will change my opinion of it, time will tell. For now I'm sceptical about the benifits of "powerbomb" exhausts on 4 stroke motorcycles.


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