Top Performance Mods for the KTM RC390 and 390 Duke

Get the most out of KTM’s mini missiles.

KTM RC390
Motorcyclist’s long-term KTM RC390 in racing trim. It definitely epitomizes KTM’s “Ready to Race” motto.Photo: Motorcyclist

If you're a regular Motorcyclist reader, you'll know that Editor Ari Henning has spent considerable effort prepping his long-term KTM RC390, turning it into a trick, race-winning machine (check out all the long-term updates here). Ari's a big fan of small displacement machines, and taking a gander at the parts he's thrown at the RC390 may convince you that he's really on to something—and make you question why you're bringing anything larger to the track.

RELATED: Onboard Video: KTM RC390 Sets Lightweight Twins Lap Record at Sonoma Raceway Modifying a motorcycle in pursuit of faster lap times doesn't always improve the road-going abilities of a machine, so keep that in mind before you start throwing parts at your bike. Still, certain improvements, like adjustable suspension that's set up for your weight and riding habits, is going to be better regardless of whether you're chasing pole position or dodging potholes.

Suspension Mods

KTM RC390
Starting at the front of the bike, replacing fork internals ($699) gives full adjustability, and is significantly less expensive than replacing the shocks entirely.Photo: Motorcyclist

Andreani fork internals: The RC390's stock inverted forks look the business, but lack of adjustability are evidence of cost-cutting at the Mattighofen factory. Replacing fork internals with ones from Andreani gives full adjustability for better front-end feel. For more information, check out Ari's full review here.

KTM RC390
The JRi shock ($899) is considerably less pricey than the WP unit ($1450) that the RC390 Cup-spec bikes carry.Photo: Motorcyclist

The 390's rear shock is also a pretty basic piece, only offering preload adjustment. Replacing the stock unit with a JRi Double-Adjustable Shock made to order in North Carolina, offers full adjustability. As you'd expect, Öhlins also makes a fine shock for the KTM. For a complete review, click here.

Performance Mods

KTM RC390
The MotoGP-inspired look of the Mivv Ghibli exhaust ($505) drops weight, lets the engine breath, and sounds nice too.Photo: Motorcyclist

Mivv Ghibli exhaust: Adding a more free-flowing exhaust to a bike is a common first step. The Italian-made Mivv Ghibli slip-on, available through MNNTHBX, is a trick item, though unfortunately limits cornering clearance—not ideal for a track bike. If you're worried about ground clearance, Yoshimura makes a dual-can underseat item ($799). The RC390 Cup bike uses an Akropovic pipe ($899), though some have cited ground clearance issues with it as well. For more information, click here.

Power Commander V: The stock RC tends to run lean, so it's a good idea to get the fuel mapping sorted out with a Power Commander. Besides, if you're going to install an aftermarket exhaust system, throwing on a Power Commander, or other fuel-injection adjustment module, is par for the course.

KTM RC390
The Yoyodyne slipper clutch ($850) is a premium product for sure, but its racing pedigree means it’s also more fragile than a conventional clutch and the slipper on the ’16 and ’17 RCs. Best leave this one for the racetrack only.Photo: Motorcyclist

Yoyodyne Slipper Clutch: 2016 and '17 RC390s have a slipper clutch fitted as standard, but the '15 has a conventional clutch. With the Yoyodyne slipper clutch installed, clicking down the box in a hurry prevents the back-end from stepping out. The Yoyodyne is considerably more fragile than the stock slipper on the '16 an '17 RC, but is more tunable, making it that much more race-ready. For more information, click here.

Brake Mods

KTM RC390
Ari on the binders at Sonoma raceway.Photo: Motorcyclist

The stock RC impressively comes with J. Juan braided brake lines. You may recognize the brand if you’re a race fan. As sponsors for the Kawasaki World SBK team (among many other top teams), Tom Sykes and Jonathan Rea sport their logo on their bikes and leathers (not that you’d have a chance to spot them, given the pair’s infrequent visits to the podium this season…).

Still, on the racetrack, the RC’s stock system is susceptible to brake fade, and its lever feel is a bit soft. Replacing the stock pads with items from Galfer, SBS, or EBC is a logical first step. While, you’re at it, bleed the system and use a high-performance brake fluid.

KTM’s factory Power Parts catalog has some sweet-looking 320mm wave rotors to replace the standard 300mm units. We haven’t used them, but they’re a popular modification, and will certainly improve braking power.

Ergonomic Mods

Don’t underestimate the importance of ergonomics on a motorcycle, particularly one as lightweight as the KTM; body placement significantly alters the weight-bias and handling dynamics of a motorcycle, so being able to move around easily on the bike is crucial. While, the stock controls on the RC390 and 390 Duke work well for the street, track time may require rearsets at the minimum.

KTM RC390
The rubber-coated footpegs of the stocker don’t provide the grip and feel of a good set of knurled pegs and can touch down before you’re at the limit of the tire. Tyga rearsets ($274) are an affordable option.Photo: Motorcyclist

Tyga rearsets: Tyga, a Thailand-based company that specializes in parts for small-displacement bikes, is not as well-known as brands like Sato Racing (whose RC390 rearsets are in the $700 range), but its rearsets fit the bill and don't break the bank.

KTM RC390
Driven Racing 51mm Halo clip-ons ($199) and top triple clamp ($220).Photo: Motorcyclist

Driven clip-ons and top triple clamp: The stock bars on the RC390 are pretty low compared to other small capacity sportbikes, but lowering them by an inch or so to get more weight over the front wheel, in addition to adjusting the bar angle, is a common modification for the track. The stock bars mount directly into the top triple clamp, so if you're adding clip-ons, opting for a slick machined triple clamp from Driven Racing makes sense. For more information, click here.

For reviews of additional products and to watch videos of hot laps and engine teardowns, check out the Doin' Time section here.