KTM’s 350 SX-F is hot property, and the pipe companies are swarming it. Akrapovic, FMF and Pro Circuit were among the first systems we tested. Akrapovic has plenty of experience with the machine working with the KTM factory team in Europe, FMF takes care of Mike Alessi’s bike in the U.S., and PC just jumped on the testing as soon as bikes were available. All are quality units that go on easier than the stock pipe comes off (which requires moving the shock out of the way). The stock pipe, like all KTM pipes, is reasonably quiet. It is a little soft off the bottom, pulls strong in the upper mid and falls off at high rpm. All three aftermarket pipes go on and off with the shock in place.KTM Power Parts
Akrapovic Evolution Full Titanium Systemwww.ktm.com
$1,599.98 (includes S/A insert, extra springs and ceramic anti-seizing grease)What’s Hot
- This system is light, a work of art and fits very well. All necessary hardware comes with it, and Akrapovic includes special ceramic anti-seize grease for the connecting joints. The included spark arrestor is also a quiet insert.
- The Evolution is very quiet for a motocross exhaust, and especially at full throttle. It measured 96 decibels on the static test and 107.5 on the two-meter full-throttle test.
- Performance overall is strong over a wide rpm range beginning with a good pop right above idle. It starts to roost with authority in the upper midrange, and it screams on top with the strongest high-rpm pull of any system.
- Quality and beauty come with a large price tag.
- The pipe is long, and the end-cap is spaced away from the bike so it risks crash damage.
- On tight tracks this pipe requires more clutch to get out of tight, tacky turns than the others.
If you like long, fast tracks with sweeping turns, or you are a bike revver, buy one.FMF
Factory 4.1 Titanium System With Meagabomb Headerwww.fmfracing.com
$899.99 (includes 94-decibel quiet insert and wash plug)What’s Hot
- The Factory 4.1 system is light, tucked in well and protected. All necessary hardware is included as is the quietest of the standard quiet MX inserts.
- The most reasonable price of the Ti systems; a less expensive stainless version is available. With the quiet insert it’s 94.5 is quietest on the static and a reasonable 108 at two meters and full throttle.
- With the standard tip the FMF has the strongest low-rpm pull, takes the least clutch and is the best pipe on tight, tacky tracks. With the quiet tip installed the bottom is a little softer. For faster, softer tracks the quiet tip is better since the bike pulls longer and harder on top.
- As delivered the exhaust note has a crack to it, and the sound is 98.5 on the static test and 109 at full throttle.
- A small rubber pad protects the plastic sidepanel from melting, but the pad’s mounting plug is delicate and doesn’t last long.
- Doesn’t pull on top as well as the Akro, but standard or quiet it has more bottom.
The best choice for tight, tacky or stadium-type tracks with short-run jumps.Pro Circuit
T-4 GP Systemwww.procircuit.com
$779.95 (includes hardware and anti-seize)What’s Hot
- Pro Circuit’s stainless T-4 system is light for a non-Ti system, and especially the header and midsection. It fits and the looks drew high marks. Since the system is stainless, it is the most affordable of these three systems.
- The standard T-4 system is middle of the road for sound, 96.5 on the stationary test and 109 on the two-meter full-throttle test. To the ear the pipe sounds louder than the Akro system, though it measures very close on the static test.
- The T-4 is a do-it-all system: More impressive than stock and effective on any track. It is fairly strong out of turns on tacky, tight tracks but still runs hard on top on the faster, more open tracks.
- The muffler section is the heaviest of the bunch.
- The pipe is long, and the muffler is long enough to be vulnerable.
- There is slightly less bottom than FMF, and less high-rpm scream than the Akrapovic.
A sharp-looking system that works well everywhere.