We Finally Throw a Leg Over a KTM RC390 Cup Bike

How does KTM’s RC390 Cup bike compare to Ari’s long-term project bike?

Start of a motorcycle race
Just waitin’ to see that green flag! The start is one of my favorite parts of racing.Photo: Olivia Godin

The little KTM RC390 rocked the small-bike world when it arrived in 2015, and it's continued to make waves as the spec bike for MotoAmerica's RC390 Cup series. More recently, KTM's announcement of a $2.3M roadracing contingency program has brought even more attention to the KTM lineup, especially the race-ready RC390 Cup bike.

The race-prepped Cup bike—which comes with over 30 KTM Power Parts pre-installed including fully adjustable WP suspension and—is the dream bike for countless kids and corner-carving adults.

I was enamored with the RC as well, but as a DIY guy I decided to roll my own ultralightweight racebike from a stock street-based RC390. After developing my bike for the track I was curious to see how my efforts compared to factory prepared Cup bike. Luckily, KTM had a brand-spanking new 2016 RC390 Cup bike for me to try. The bike I rode was fresh from the crate and totally stock except for tires—we swapped out the glossy Metzeler rubber for my scrubbed-in Pirelli Supercorsa SC track tires.

I installed Driven clip-ons on my bike to lower the grips, but the Cup bike retains the stock, triple-clamp mounted handlebars which I assumed would make the bike feel awkward on the track. (They certainly do on the street.) Surprisingly they feel natural on the track, likely because you spend so much time either fully tucked in or leaning off the bike.

KTM RC Cup graphics
Thrashed leathers, fresh bodywork. The RC I rode is rocking the new Cup-bike graphics. It’s a sharp-looking little machine.Photo: Olivia Godin

Speaking of leaning off the bike, I’ve heard from many Cup-racer kids that the bike drags hard parts at lean. Admittedly I wasn’t on my normal race pace when I rode the RC at Chuckwalla this past weekend, but I only ever dragged hard parts occasionally, and even then only on curbing. That being said, the bike did feel soft, which is a common complaint among RC racers, especially the bigger and heavier ones.

The bike’s soft suspension means you can’t flick the Cup bike around as aggressively as I would have liked. (For the record, I weight about 185 pounds in gear, which is quite a bit more than most of the 16 – to 22-year-olds that race in the MotoAmerica Cup class.) That’s one area where my long-term RC and its custom-tuned suspension really excels—you can slam the thing from side to side and be very forceful with your inputs. On the Cup bike I had to be gentle and very smooth so the suspension wouldn’t get overwhelmed and start wallowing. I’d compare it to the way you need to ride in the wet, which, if you’re looking to train kids how to ride well, isn’t such a bad thing.

When I rode the Cup bike among fellow ultralightweight racers at Chuckwalla I was frustrated by the delicacy that the bike’s softer suspension demanded, but as a spec bike, where everyone has to deal with the same suspension, it’s not such a downer. Same goes for the spec Dunlop Alpha tires. I’ve ridden on them and don’t like them (they don’t have much feedback), but if everyone has to ride on the same thing then the playing field is level. That’s the whole idea behind spec racing.

KTM turnkey race bike
Motorcycling hasn’t seen a turnkey racebike since the uber-expensive Moriwaki MD250H. The $10,000 Cup bike comes outfitted with WP suspension, upgraded front brake, engine covers, adjustable levers, race bodywork, and more.Photo: KTM

One area where the Cup bike beats my long-termer is in the braking department. The upgraded 320mm petal rotor offers a lot more power and feel than the stock 300mm rotor, even after I'd slid in EBC HH pads and bypassed the ABS module. The RC's machined and adjustable levers are pretty trick too. The Cup bikes have the ABS module disabled as well, which means there's no anti-lock function, no speedo readout, and no trip meter or odometer. I kept the front-wheel speed sensor on my bike so I've at least got dash functionality.

There’s one more thing that catches Cup-bike owners and potential Cup-bike owners off guard, and that’s the bike’s limited power output. Stock street RCs make about 40 to 41 hp, but the RC390 Cup bike is limited to 38 hp to match the power-to-weight ratio of a previous spec bike that was popular in Europe. Despite giving up 5 peak horsepower to my RC project bike (that’s 13 percent), the Cup bike didn’t feel any slower and I could easily pace Yamaha R3s and Ninja 300s on track. I’m thinking that the Cup bike’s specific fuel and ignition timing does a better job of propping up midrange power than the slapdash tune I have on the Power Commander on my bike.

Other differences? The Cup bike’s slip-and-assist clutch has a drastically lighter lever pull than the six-spring, non-slipper setup that came stock on my first-year (2015) RC390. The Cup bike’s Akropovic exhaust is also whisper quiet, which is a little odd for a racebike. Other than that the factory bike and my project bike turned out pretty similarly, though of course I’m more comfortable flogging my project bike since it isn’t so damn brand new. The biggest difference is the suspension setup and ergonomics, both of which are personal-preference things that tend to get tweaked to suit the rider.

All in all I’m pretty impressed with the Cup bike, though of course I’m still happy I built up my own RC390. And the Cup bikes are supposed to be getting better. I’m not allowed to divulge details, but I’ve heard from KTM insiders that some exciting changes are coming for the little orange roadracer. Stay tuned for more.