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FMF Mega Bomb

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I'm planning on ordering the FMF Mega Bomb for my 07 KX250F this weekend, but there is a little confusion. FMF's website states that the Mega Bomb header works with the stock pipe or one of FMF's pipes. But I have heard a few stories on ThumperTalk about the Mega Bomb header not fitting the stock pipe.

Anyone on this forum run the FMF Mega Bomb header with the stock pipe or know of anyone with this set up. Will the Mega Bomb fit the stock kx250f pipe?

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I have the FMF factory 4.1 slip-on. The outside diameter of the stock header is smaller than the inside diameter of the mid pipe. This is with the aluminum insert installed. I would imagine the Mega bomb header would be too large for the stock pipe without some modification. Maybe if of shaved down the black insert on the stock pipe it would work?

I am no expert. Trust me.

:applause:

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Your stock header is better. Unless you've damaged your stock pipe, I'd suggest you keep it and buy a silencer in stead.

Why is that?

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Your stock header is better. Unless you've damaged your stock pipe, I'd suggest you keep it and buy a silencer in stead.

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Your stock header is better. Unless you've damaged your stock pipe, I'd suggest you keep it and buy a silencer in stead.

I beg to differ, not true. More power is made with a header. The length, thickness, and steps of the header have a lot to do with how the power is made. I'm not looking to make my bike louder, I'm wanting a little bit more usable power. I like the idea of the Mega Bomb too. Creates bottom end of a long header and top end of a short header. I'd much rather buy the Mega Bomb and get a decent gain in overall power than spend $500-800 on a full system and get similar gains in power.

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I plan on picking up the mega-bomb next week as my b-day gift to myself. If you can wait I will see how it fits on the stock mid-pipe and exhaust and post my results.

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My last dirt Rider had a 450F test in which they added the Mega Bomb to the stock Yamaha silencer. The implication was that they could have added the mega bomb to any of the others as well. Not quite the answer you wanted but close.

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Every Mega Bomb header I have sold is used with a 3 part system (Header, Mid pipe and Silencer). The mega bomb is to short to reach the silencer of the stock system.

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It is my understanding that the megabomb will fit stock or any FMF muffler.

And while head pipe length and diameter will move the power around somewhat. The largest gains I have seen on the dyno is with the slip on's. No way will the megabomb alone on a stock muffer outperform a slip on with the stock head pipe on the dyno.

Head pipes like the megabomb help fill in the gaps in the power curve and complete the full system. Generally head pipes move the power around and the change is close to .5HP. While slip ons alone make a change from 1 to 2 HP.

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The stock Header works very well and out perfroms the FMF megabomb. You can tune the megabomb with different muffler end cap sizes. Best combination however is stock header and FMF slip on.

If you are worried about not having the bling factor remove the guard from the stock header and tell your mates its a prototype FMF high flow header.

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I don not see how the stock header can out perform the mega-bomb. Do you have proof of this? Please enlighten us if you would.:applause:

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I don not see how the stock header can out perform the mega-bomb. Do you have proof of this? Please enlighten us if you would.:applause:

On the track and on the dyno the stock pipe produces more HP everywhere. The megabomb is additional silencer to allow you to still run a non restrictive muffler. This is only my experience.

Does anyone have a dyno graph showing gains from the megabomb header?

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hummm i don;t think a BIG company like FMF would prodouce a header that reduces power....and ppl wouldn't use em

Why do you assume that FMF can make a header pipe better than Kawasaki?

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hummm i don;t think a BIG company like FMF would prodouce a header that reduces power....and ppl wouldn't use em

Kawasaki could buy FMF with change from their lobby couch! FMF must have a header pipe to sell or look foolish. I'm not picking on FMF, several of the aftermarket pipes are not as good. Kawi did their homework with their pipe and it's very hard to improve upon for motocross. For off-road, the megabomb helps with noise and moves the torque lower. :applause: You will, however, sacrifice some top end.:applause:

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