Gonna add an FMF header to my pig over the winter and was wondering if yinz could give me some input on whether to buy the standard header or opt, for an extra 40 bucks, for the power bomb model. Is this thing a gimmick or does it actually do something:confused: Thanks man.

Starting to cool off out here in the "Buckeye". Riding weather is winding down. :thumbsdn:

I run the FMF PB header on my bike, and compared to the stock header there's a definite improvement. When I first fired it up after installing it I noticed that it had a lower "rumbling" sound compared to the stocker. I also noticed that it has more low end grunt now. It's made of Stainless Steel and is easy to keep looking good, although I would advise wiping it down with acetone to get any fingerprints and other oils off it before firing it up for the first time, because if you don't it will stain the SS once it goes through it's first heat cycle and once it has those stains on it they're a bugger to get off. :blush:

I can't compare it to the other aftermarket headers though (XR's Only, etc.), because I've only run it and the stock one. :cheers:

I found the powerbomb to be slightly quieter. I would have liked larger diameter head pipes though.

+1 to the cleaning the header before you start it. I do a good spray down with brake clean and then a nice coat of wd40. Every stainless header I have done that to turns a nice even golden brown. If you want to remove purple spots and the gold, soak the header down with some etching mag wheel cleaner from Eagle One. Wait about 60 seconds and then hose it off. The stainless will return to its original silver color and stay that way for some time. I believe the chemicals in the etching wash create some sort of protective oxide layer.

+ 1 on the PB header being "quieter" I am running the FMF Powercore4 with the PB header, I think it is a nice set up. Quiet until your whack the throttle, then it barks pretty good. For Dual sport use I like the ability to run at low RPMs and not turn heads...until I want to!
I am ashamed to admit this, but if you wet sand the header with 1000 wet/dry paper you can make the header look like chrome. It wont last long though.

If the tubing sizes are the same, I would get the cheaper regular header. One of the big no-nos of designing an exhaust system is having the tube increase in size and then get necked down again....and that's exactly what the PB does. Their own description of how it works even says that it wastes exhaust energy, although it's worded to sound appealing. It likely does flow better than stock, but I highly doubt it's any better than the regular header.

Regarding tube size, my Yoshimura header has primaries that might be considered small. I think they are only ~1.5" O.D. before stepping up to 1.625" and going into the collector. Together they have the approx. flow area of a single 2.12"/54mm tube, which I guess to be enough for ~100hp.

Old Graybeard said:

On the 650R the power bomb is a waist of money. If you want to spend more money and get a pipe that will give you more HP then go with the Pro-Circuit system or better yet, get the XR's only race system.

I love FMF for many applications and their quality is great but they didn't pay attention on the 650R. I put on Power Bomb and really didn't notice a difference over the un-corked stock header and muffler. It was really noticeable when my friend on a stock 650R with the un-corked stock muffler could pull away from me on top speed with the Power Bomb and FMF muffler on mine. For the guys who jump in and say it's jetting... no, it wasn't jetting.

Also, don't worry about losing torque on a 650R! Go for top end performance as there is so much torque you will never wish you had any more.

So to answer your question, if you buy FMF the hi-flow is just fine (save the money).

Thanks for the input....big help. OGB

+1 PB for the XR650R is a waste. They benifit from well flowing exhausts.

i haven't seen a dyno for the powerbomb's but i have seen sum impressive dynos for the megabomb on crf's and KTM's...they bumped the torque across the chart and the peak HP numbers :thumbsup:

...of coarse the Ti megabombs are $350 for just the header :eek:

i picked up a practically new FMF Hi-Flow and heatshield for a $160 on ebay...just get'n ride of the pitted mild steel stocker was worth it but there wus a slight performance increase :thumbsup:

without additional engine work don't expect much other than a little topend.

:cheers: