FMF Racing Titanium 4 Exhaust System

APPLICATION: All current model four-strokes; tested here on the 2003 KTM 525SX.
PRICE: $799.97 for complete system; $274.99 for Ti Powerbomb, $174.99 for Ti mid-pipe, and $249.99 for Ti 4 silencer.

Back in the November ’02 issue of TransWorld Motocross, we tested KTM’s biggest thumper, the 2003 525SX. Among the bike’s notable mannerisms was a mellow powerband, which made it easy to ride. We also felt that the gentle giant had better throttle response than the’02 model, and though it wasn’t as snappy as some of the smaller “race” thumpers, it was easily able to pull out of most turns in third gear.


Brand new for ’03 is FMF’s Ti 4 Exhaust System, specially designed for the big pumpkin. Upon opening the box from FMF we were immediately impressed by the apparent lack of weight for the system. It felt as though the header barely had any heft to it at all. As we looked closer at the entire system, the components were obviously crafted with pride. The welds, bends, and even the placement of the spring hangers were all perfect. To see actually how much weight we were saving, we threw the stocker on our scale and it came in at just under 10 lbs. When we replaced it with the Ti 4 system, it dropped into single-digit range…in fact, it was only five pounds! That’s a 50% weight savings from the stock items! If the Ti 4 setup could put our big Katoom on this kind of a diet, we couldn’t wait to open it up on the track and see if the performance gains were as substantial as the weight savings.

Bolting on the Ti 4 was a snap. It only took 10 minutes to pull off the old chrome stocker, and put the svelte new FMF combo in its place. A couple noteworthy things: You’ll need to remove the bottom shock mounting bolt and move the shock over. This enables the header to move freely through the subframe. Also, the brackets used secure the Ti 4 silencer are awkward to maneuver into position. It’s almost like doing a juggling act. You have to hold the o-rings in place while moving the bracket and if that’s not enough, put a spacer on the end of the bolt! Make sure you have an extra hand or two available when installing the unit. That said, when the Ti 4 can is finally bolted onto the subframe via the mounting brackets, they give it flexibility not found on the stocker.


As soon as we kicked over the big-bore, we sensed that it could finally breathe. Better yet, once on the track, the throttle response was unbelievable. This combo turned our gentle giant into Godzilla! Gone was the tame acceleration the bike had previously enjoyed. Now the big Katoom acted like a hopped-up race machine on steroids. Crack the throttle if you dare…the bike will set your eyes back in your head, and pull your arms out of their sockets! Power was up everywhere, and without the need for re-jetting. We even caught ourselves seat-bouncing jumps out of turns!


The guys at FMF have obviously done their homework on the Ti 4 combo. If you own one of the new KTM big-bore four-strokes and want to put your bike on a strict diet while simultaneously giving it a power boost, the cost of the Ti 4 system is money well spent. Call 310/631-4363 or visit