I was wondering if anyone knew what was inside the little bubble part of the powerbomb. Is it just open or does the pipe have a bunch of holes in it and then the bubble is put over it or is it something else in there.

I remember seeing FMF adds where they were showing pics of copycats of the design and got me to thinking about doing a little surgery on the muzzy header.

 

FMF Racing Power Bomb

• A 4-stroke header system that incorporates FMF’s patented Power Bomb module at a precise location in the initial stage of the header system. By positioning the “Bomb” at this key point, the expansion and contraction of exhaust sonics through the system results in a flow increase of nearly 10%
• The surface of the perforated core lets the sound exit into the absorbing material (steel wool packing) and then allows the air to expand, cool, and ramp back up at air higher pressures (RPMs).
• The Power Bomb is a “pre-muffler” of sorts, which helps to lower the bikes sound output because it provides more sound absorbing surface area to allow the exhaust gases to become bsorbed

 

I've used FMF silencers on past bikes and been impressed. As far as the "Power Bomb" goes I've always thought it was just a marketing gimmick- I'd like to see them back up those claims....

 

I'm curious too, so I poked around and found this out.

Inside is a straight through pipe with some holes, then the "bomb" part wraps around that. If you wanted to copy it, you would drill holes in your header at that location, then weld on the "bomb" around it. I don't know how many holes or their exact locations because haven't actually seen it myself, just going by others' descriptions.

Here's about the best description I can find of its operation, post #3 of this thread:

http://www.thumpertalk.com/forum/sho...27#post5999327

 

Found a cut-a-way view. Sorry it ain't in English.

http://www.motorrad.gol.at/produkte/2003/fmf/index.html

 

looks like a good place to drill a hole and weld in an O2 sensor

 

I had hoped to find a reversionary cone or somethin spiffy...but I bought into it. The wifes butt dyno said mid range is better, sounds throatier, also used a 132dj main