Sorry to add another thread to the previous billions in terms of exhaust, but my search didn't really turn up anything that was to the point i was looking for.

Basically my question is this, does the FMF megabomb header really do anything in terms of power gains ? I really like the look of the muzzy but i am intrigued by FMF's claims on power increases with the megabomb header.

The reason i ask is that the FMF header seems to be overly large and without a heat shield i am a bit concered about buring myself or setting my pants on fire with its giant "tumor".

I understand the benefits of an expansion chamber on two-stroke engines what with the added volumetric efficiency and exhaust pulsing all that, but is it really beneficial on a four-stroke engine with regards to the valves and all ?

It would seem to me from what i observe on supersport bikes that a large diameter free flowing exhaust pipe is all that is needed. I've never seen a sport bike (other than two-stroke machines) with expansion chambers.

Is this a attribute to single cylinder four-stroke engines, the need for an two-stroke style expansion chamber ? The klx is the first four-stroke thumper i've owned so i am sorry for my ignorance in the matter but any insight would be greatly appreciated.

 

I would have to see dyno charts before and after , before I spent a bunch of money on it. I have always thought they were a sales gimmick.

 

Marketing loves things with catchy names....like Power Bomb. Maybe there is something to it, but, I'd have to see it on a dyno to believe it, and compare it back to back with others, and have the difference be repeatable with other dynos and bikes.

 

I agree. Lets see some dyno charts FMF proving that expansion chamber works on a 250cc engine or some lap times to get a real would effect.

I would gladly pay the price if I knew it would increase power.

 

do you think your actually going to feel .2 hp? if your worryed about looks then just get what you want and youll be happier in the end. sales gimmic or not, i got one.

 

If it comes down to a level like that, I would rather have a traditional head pipe design.

My goal is a solid 30 hp with a BB351 and TM36-68. I'm going to have the head ported and polished as well.

I love this bike and even with the money i will sink into it with the BB and pipe, head work and carb i will still be less than a WR250 or something along those lines the way i figure.

Thanks for the replys at any rate.

 

just go with the pipe you like the best, at the end of the day, it is the same engine, port, valves and all the pipes are similar size and straight through headers and slip on.

best thing i can suggest is wait till a 2nd hand one comes up and go for that.

 

Agreed go with the one that fits both your bike and your budget. I had the muzzy on mine and it fit really well. The only thing I didn't like about it is how far the can stuck out towards the back.

My brother has a big gun on his and it also fit really well, less the slight touching of the pipe to the air box. Big gun tucks away a bit more like a dirt bike.

Both had great power, no real difference in either other than looks and sound. I'm sure the FMF is similar.