Tested: FMF Factory 4.1 RCT Muffler

A product the Transmoto team has tried, tested and would recommend to a mate.

WHAT IS IT?

Developed specifically for Husqvarna’s 2020 FE models and available through the Husqvarna Accessories catalogue, the FMF Factory 4.1 RCT Muffler is made from high-grade titanium with a blue-anodised outer sleeve and carbon end-cap. It can be fitted to the OEM header/mid-pipe or mated with an FMF Megabomb header, and comes with optional spark arrestor mesh insert. It’s claimed to be lighter than the OEM muffler and generate gains in both torque and power.

Having run the FMF Factory 4.1 RCT (“Resonance Chamber Technology”) Muffler on our 2020-model Husky FE350 project bike for a few months, here’s what we can tell you about it…

WHY WE RATE IT

PROS…

• Performance: An improvement in throttle response is instantly noticeable with the FMF muffler bolted on. It gives the FE350’s power a snappier, livelier character (especially at lower revs), and by getting into the meat of the power earlier in the rev range, the bike becomes a lot easier to ride in stop-start terrain. You can get away with using less clutch to keep the engine on the boil, and it responds better to short-shifting. Basically, it brings back the sort of punch that most Aussie riders like to get with smaller-capacity machines (which was lost to some extent because of the changes to the 2020 model’s mapping) and it lets you capitalise on the other engine mods the 2020 FE350 came with (more compression, new camshaft, sweeping cylinder head mods, etc).
• Weight: Even with the spark arrestor insert fitted, the FMF muffler is almost half a kilogram lighter than the OEM unit (2105g, versus the OEM’s 2572g), and almost 600g lighter if you run it without the insert (1983g versus 2572g). That might not sound like much, but remember that reducing weight at a bike’s extremities pays bigger mass centalisation handling dividends.

• The Fit: As you’d expect from exhaust specialist, FMF, the built quality and fit of the muffler is superb. Tolerances are excellent and the mounts line up perfectly.
• Noise: Without the spark arrestor insert fitted, the FMF pipe barks a fair bit louder than the stock muffler. With the insert fitted, however (interestingly, this doesn’t affect power or throttle response, except at high revs), the FMF’s exhaust note is only slightly louder than stock, albeit with a deeper, meatier and more appealing tone.
• Looks: Blue-anodised titanium, carbon end-cap, billet mounting brackets – yep, there’s a lot to like about the FMF muffler’s aesthetics. It almost too nice to take bush and scratch the thing!
• Price: Earlier this year, the FMF Factory 4.1 RCT Muffler cost $1170, but it’s now been reduced to $869. That’s a fair chunk of change saved, which brings it much closer to the price of an OEM muffler ($569), FMF’s Powercore 4 Silencer ($659), and is a whole lot cheaper than the other titanium option in the Husqvarna Accessories catalogue, the Akrapovic Slip-On ($1349). Viewed in that context, the FMF Factory 4.1 RCT Muffler represents great value.

CONS…

• Accessories: If you buy a new muffler, it’d be nice if it came with all mounting hardware required. Sure, the FMF Factory 4.1 RCT Muffler comes with a spring, but you need to tear the rubber grommets and alloy collars off the OEM muffler and re-use them with the FMF. As these grommets tend to perish after about 12 months, it’d be nice to get fresh rubber with the FMF muffler.

There’s something very gratifying about bolting a part onto your bike and immediately feeling the performance gains. And that’s why free-flowing mufflers have long been one of the most common aftermarket mods. This FMF Factory 4.1 RCT Muffler certainly offers significant gains over the stock muffler – in terms of throttle response gained and weight lost (and because the muffler on Husqvarna’s 2020 four-stroke enduro bikes is more restrictive than what’s used on their KTM counterparts, the boost in power and torque it generates is relatively bigger). We suspect even greater gains could be had if this FMF muffler was coupled with mapping mods. Which is exactly what’s now in store for our FE350!

PRICE: $869.99 // Husqvarna Technical Accessories