By John Bumgardner and Tom Webb
I’m a full-gonzo EXC nutcase—but of the 500 vintage. For the last two years this has been my main squeeze since a majority of our off-road is now peppered with a network of tarmac. These machines have been a godsend, especially for someone who needs to get to the good stuff but doesn’t want to be zip-tied to a pig when the going gets ugly. I crave a machine that has tattooed on its side panels “barely street-legal.”
This year I’m switching gears for my dual-sport mule of choice and going with KTM’s 350EXC. My gaggle of BSL (barely street-legal) cohorts question this decision, concerned that my larger size may leave a bad taste in my mouth when the trail gets vertical. Actually, they said, “You’re too girthy for a pea popper!” Deep down, I know that I may give up a bit on the hills, but I will work them when the going gets tight, technical and a tongue-dragger.
There have been incredible performance gains in the short time that the 350 has been on this earth. KTM started with the goal of building a mid-bore big bore, but the first year’s machine was actually an enhanced 250F with a smidgeon more bottom power. Earlier this year, I tested the new 350XC-W at a National Enduro, and that’s what motivated me to pick this as my BSL machine. The new one makes better bottom power, the fuel injection is mapped ideally, the six-speed gearbox is well-spaced, and the chassis and suspension work well for my passion, which is versatile off-road. I was hoping the 350EXC would mirror the XC-W’s performance traits.


Starting with the engine, the EXC has a heavier crankshaft than both the SX and XC-F, targeting increased traction and slow-speed control. The dual overhead cams run via titanium valves that allow for extreme engine speeds that hit the 12,000 rpm elevation point. The cams are designed for a more enduro-specific lower rev range than the SX, which helps with the necessary bottom-to-mid power. There is also a redesigned auto decompression for improved starting habits. The crankshaft drives a laterally positioned intermediate shaft that also acts as a balancer shaft, water-pump drive and timing chain drive for the two camshafts.
The 350 uses the DDS clutch. The damped diaphragm steel has a single-piece outer hub that is fairly thin, courtesy of the rivet-less design. It uses a diaphragm spring rather than multiple clutch springs and allows for additional hub damping, which helps with transmission wear. It’s equipped with a six-speed transmission (the SX has a five-speeder) and is a wide-ratio, targeting a little broader spacing than the SX, with an overdrive sixth for longer pavement sections. The EXC is geared super tall (14-45), which is one of the ways that the machine meets the noise level requirements to be street-legal.
On the fuel-management system, the EXC uses a similar 42mm Keihin throttle body with a number of “closures” to keep it from getting modded by hot rodders. It is on the lean side because it has to pass efficiency guidelines targeting pollution. Lastly, KTM fits the EXCs with a strong, 196-watt alternator that powers the 55-watt halogen light, fuel injection and other electrical loads. Exhaust-wise, the EXC uses a stainless header that mates to a new muffler that now has a non-removable screen (last year you could remove it) at the muffler’s end piece. This has helped reduce noise even further.
The EXC uses the new 250 frame, which is equipped with thinner-walled downtubes, making it lighter. The cast swingarm targets lighter weight, with stiff points at strategic zones. Like the XC-W off-road line, the WP fork is a 48mm, open-cartridge design with adjustable spring preload and both compression and rebound circuits. The open-bath system offers plusher action than the closed-cartridge system used in the SX or the ??4CS1?? design in the XC-F. The rear end’s absorption comes via a WP link-less shock that has been the staple of KTM off-road bikes for years. While motocross bikes and closed-course, off-road bikes need linkage to help deal with the higher shaft speeds in the shock, courtesy of whoops and other obstacles that stress the shock’s ability to react, enduro terrain is all about smoothness and traction. This is where the lighter (around 5-plus pounds) link-less design is magic. Also, it makes removing the shock a five-minute job rather than 35 minutes.
It has cast triple clamps rather than machined, because they have found that cast helps keep the fork action more supple, which is good for the off-roader. The front fender is new (and bolts up differently), rather spacey and 50 percent stronger. The clamps are multi-adjustable (fore and aft, plus perch offset) and attached to Neken bulge bars, which are strong and have a good bend. Renthal grips, a Brembo hydraulic clutch and miscellaneous street electrics inhabit the bars’ real estate. They’ve redesigned the handguards, and they are now a two-piece system that bolts to the clutch and brake perches.
The brakes are Brembo, and the brake piston has been changed to enhance smooth power. Both hubs are machined and use black aluminum spoke nipples and Maxxis DOT tires, which got great reviews last year.

Our first test of the machine was in stock trim, including the gearing. Normally, the 14/45 sprockets are something that we’d leave on for roadwork but would swap out for taller cogs as soon as dirt came into play. Here’s how it went.
Starting stone cold is doable without the choke, but it doesn’t like it. You have to keep at the button eerily long, and then all of a sudden it lights. With the choke, it’s immediate, though it’s a nightmare to find the sucker. There’s a rat’s nest of paraphernalia under the left side of the tank and in front of the throttle body. First gear is way too tall, second naturally more so. On the street, this wasn’t a problem. In the dirt, nearly every tight trail was all about first gear and second only when it opened up substantially. We tested this way on our 45-miler, a trail system with some good hills, lots of tight turns, ruts, gotchas and serpentine rock zones. Actually, the bike was amazing geared so tall, and there was far less struggling on the hills than anticipated.
Power-wise, the 350 is quite a bit softer than the XC-W and way mellower than the XC-F. Still, it’s very trail-friendly. The engine feels light, has little decel and ekes out just enough adrenaline down low to pull the machine through the trails. And, man is she quiet! Part of our route takes us by horse properties, and the well-honed survival traits of the ponies were barely aroused when we putted by. Once you motor past the mild bottom power, the 350 seems to pull decently for as long as you can twist it. Mid-to-top juice is impressive!
In the handling department, the 350 feels a bit heavy and is fit with spring rates that target a 180-pound pilot—max. At two bills plus a 20, I struggled here until I went back home and bumped up both the fork and shock spring rates. This helped me monumentally, keeping the bike higher up in the stroke. The bike’s high-speed habits were improved, and it still carved quite nicely. So, in my first 100 miles of trail testing, the biggest drama I encountered was a little bit of Stanly Steamer action (there is no fan on the 350) and a high wallow factor—until I went with heavier springs.
For round two, the only change I made was to the gearing. I dropped the front countershaft sprocket to a 13 and upped the rear sprocket to a 50. Unfortunately, this meant that a new chain was in order, so it wasn’t a cheap update. But, this one change was dramatic, and I found the bike started to feel nimbler simply because I now had power attached to proper gearing. My speed and control were amplified, as having usable ratios made the soft power feel more suited to conquering terrain. It would now pull and sort of chug, whereas with the stock gearing it was all about momentum.
I had no issues will stalling, flameouts or glitches in the power during the next month and a half of testing. Every street-legal piece, including the seemingly crushable rear taillight/plate holder, held up fine under the duress of my tonnage. In a shotgun burst, here are the quick and nasty points that I’ve noted.
–Seat is too low for my creaky knees; thankfully, I have a tall Enduro Engineering saddle and fixed it.
–Then the bars were too low. I installed two 5mm EE spacers and put the perches in the front holes.
–I have no idea what gas mileage the 350 gets, but is has to be stunning. On my 45-mile loop, I used way less than half a tank.
–The odometer/clock is the same unit KTM has had for years, and once you know how to program the modes you want (I like speed and a resettable odometer), it works well. Guys with old eyes will have issues picking up the small readout.
–For some reason, the shifting seemed a little notchy. I’m hoping that it smooths out with time on it.
–Only boiled it two times when flogging in the tight. Still, does a fan make sense?
–No skid plate? Come on.
–I broke off both of the new two-piece handguards at the plug-together points. I’ve since drilled them out and used nuts and bolts, which solved the problem.
–The stock mirror is worthless off-road. I switched to a Double Take unit. It kills it off-road, and you can actually see traffic behind you on the pavement.
–The rear brake is touchy and the front is strong. I can deal with the front, but I’m going to try a different pad out back and try to soften the stickiness.
It’s weird, but there are some places where I feel that the 350EXC is a good bike and others where I’m struggling trying to find the right gear. Overall, I’m really stoked with the scoot, especially since I’m really abusing it on good, tough trails, and the engine and exhaust are totally EPA-legal. It’s beyond quiet, it’s rugged, it craves trail junk, and I can ride it to work.
What does the near future hold for this wagon? I’ve already had Precision Concepts valve and spring the suspension (see sidebar), bolted on Pro Moto Billet/Fastway handguards and a steering damper system (again, see sidebar), and am testing some of the new Fastway Evolution pegs (better ergos for my stature). I’m on my third set of tires, and I’m finding the more time I spend on the 350EXC, the more I smile. This machine has Wolf written all over it. o


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