I've searched this particular forum and others and still haven't found a truly definitive answer to my question:

What aftermarket header will work without *any* modification with a Two Brothers M7 slip on? Bike is an'09 SF.

I'd like to buy an FMF Powerbomb but not sure it will fit without mods.

The Two Bros. came on the bike and I'd really rather spend my money on the 331/351 big bore kit soon instead of a new full exhaust system.

If I can find a header that will work with the Two Bros. that would be great.

Also, I've already tossed 35 bucks at the Two Bros. for the quiet insert....

Two Bros. has the header available separately for 140$ but not sure what/if the performance gains are.

 

mel, I never really thought about this before, but after poking around a bit, it seems that many slip-ons of one brand or another don't fit the aftermarket header in many cases...the obvious difference in header pipe diameter and even bend radius in some cases. Unless you find someone who's done exactly what you're trying to do, I think I'd go with the 2-bros pipe if they can absolutely confirm that it will fit with their full header. The 2-bros header looks good, and I'm not sure there are huge differences in performance in the full aftermarket exhaust systems on a KLX. The stock header is such a wimpy soda straw, and I think that's where the big gain is regardless of who you go with. Like you I think that powerbomb concept may have some credibility, but honestly I think it might only be truly noticeable when your're talking about real race motors at the higher end of the food chain...CRF's, KXF's, etc.

 

I agree with TNC here, I've got a powerbomb on mine and feel it added some punch to my low end but is that from the bigger pipe or the little chamber. Mixing and matching don't always work that well and if Two Brothers makes a header I'd go that way in hopes of a good fit and I dought you will be missing very much at all from the PB.

 

Thanks guys.

I called Two Bros tech support and they confirm that their full exhaust header pipe works with their slip on. It's sold as a 'replacement' part for the full system.

I reckon I'll go with that and be done with it.