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I got a 09 yz250f just bought a fmf powerbomb header with a powercore 4 exhaust and when I topped it out it only went 60mph and every gear acts like its 1st gear but with stock header it top out at 73mph do I have to rejet or redo gearing (I believing gearing is 14f 49r)

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I was looking into buying a FMF power bomb with an exhaust until I started reading up on some of the threads on here. I guess you end up losing more bottom end power and makes your bike slower from what the other guys on here were saying.

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7 hours ago, fidd said:

I was looking into buying a FMF power bomb with an exhaust until I started reading up on some of the threads on here. I guess you end up losing more bottom end power and makes your bike slower from what the other guys on here were saying.

Shit I hope not 

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I do think that the pipe has some different jetting needs.  FMF has a site where they give their suggested settings.  My experience with shops on jetting is not current since I have not had one do any jetting for me in just short of 50 years. Most of them are not going to do anything too far from the book,  if at all.  Hardly any of them will take one out and work up your jetting.   If they have no place to test it besides the alley my guess is they might look on fmf's site,  and they might even call them.   And charge you.   It is pretty easy if you have never done it,  and you can set the float (something it very likely needs while you are in there.)  There are enough threads,  stickies,  and people who have done everything on bikes like yours on thumpertalk that until you need some machine work done,  you won't ever need a shop again.   

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