LONG-TERM KTM RC390: Major Success at Sonoma Raceway!

The RC390 comes into its own in Wine Country.

KTM RC390 racing
The RC390 powers out of Sonoma’s Turn 9a chicane during Sunday’s 350 Production race.©Motorcyclist

WRIST: Ari Henning
MSRP (2015): $5,499
MILES: 3,489
MPG: n/a
MODS: Pirelli tires, trophies!

When I last checked in I'd just endured a rocky race weekend at Chuckwalla Valley Raceway. Between a debilitating electrical issue (since remedied, see link above) and difficulties with rear chatter and tire wear, I left the track feeling pretty frustrated.

Coming off a weekend like that I was a little apprehensive to load the RC390 into the van (along with a very cool Yamaha FZ-07R racebike that Zack had borrowed) and drive 350 miles north to Sonoma Raceway to compete with the AFM. Sonoma is one of my favorite tracks on the planet, and I was worried the RC might let me down and spoil my weekend.

RC390 hard braking
One of the fun things about Sonoma? Maximum-braking zones. Five of ‘em! The RC390 sheds 60 mph and 3 gears on the way into Turn 7.©Motorcyclist

I shouldn’t have worried. The RC390 worked better than ever, and I was able to enjoy Sonoma to its fullest. The track is deliciously technical and has drastic elevation changes, demanding chicanes, and several maximum-braking zones, and throughout it all the KTM felt planted, agile, fast, and willing. It’s the first time that I really felt like I was working with the bike instead of struggling to tame it or bend it to my will. The weekend went great, and the RC took three wins and even set a new lap record for the Lightweight Twins class. See the record-setting lap in the onboard video below.

Part of the improvement came from the softer, grippier Pirelli Supercorsa SC tires I was running, and some of it was the track. Different tracks play to different bikes' strengths, and thus far I've only raced the RC at Chuckwalla. Sonoma is distinctly different—different speeds, different rhythm, and most importantly, different pavement. Sonoma's surface is far less abrasive, so the Pirellis wore beautifully while still offering the improved traction, stability, and line holding that I experienced when I first tried the tires at Chuckwalla. The Supercorsa SCs are far and away the best tires I've used on the RC390.

Pirelli Supercorsa
The Pirelli Supercorsas have a flexible carcass that really compliments the RC’s chassis. They also wore beautifully. After the weekend they still looked new. No joke, look at the picture!©Motorcyclist

Even though the KTM worked really well, its performance wasn’t flawless. Another difference between Chuckwalla and Sonoma is the presence of five maximum-braking areas. (Versus two less intense braking zones at Chuckwalla.) The heavy use proved too much for the RC’s front brake, and after a few laps I was getting brake fade. I bled the system (and I long ago removed the ABS plumbing and installed EBC double-sintered brake pads) but it didn’t help, and I had to shift my brake markers back as the race progressed.

Brake fade is a bummer, but a soft brake lever couldn’t damp my spirits. I love riding at Sonoma and the RC390 was a great dance partner. I’ve got a couple of months until the next race, so I’ll use the time to figure out a solution for the front brake (I’m thinking an air scoop on the fender, or perhaps a different master cylinder). I’d also like to put the KTM on a diet. It’s already pretty light, but lighter is always better!