A lipstick red motorcycle propels our writer around Sardinia’s serpentine north coast—and into stony strongholds of the ancient Sards.

"You must make me a promise," says Irene Martini, a longtime summer visitor to Sardinia. We're sitting by the harbor of Porto Cervo, where million-dollar yachts are parked six deep. "Promise that you won't be seduced by the charms of Porto Cervo and the Costa Smeralda." Martini was concerned that I would be so dazzled by the coast's stylish hotels and multistarred restaurants that I would miss other aspects of this, Italy's second largest island, after Sicily.

Sardinia's "Emerald Coast," a storied land rimming the island's northern tip and including Porto Cervo, is heralded as much for its celebrity vacationers as for its beauty. I had found my way here on a multiday drive that I had been wanting to undertake for some years.

Italy is not short of great drives—think the Amalfi Coast, the back roads of Umbria, the dramatic Dolomites. But the coast of Gallura, Sardinia's northernmost region, has to be one of the most ravishing. Every bend of the road offers another expansive panorama of azure seas, of stark granite headlands, of beaches framed by fragrant juniper and oleander and myrtle. Still little known by most Americans, it is a corner of the Mediterranean adored by Italians and in-the-know Europeans.

My drive, along the wiggly northern coast and across the island's rugged spine, would take me five days. This being Italy, I felt I needed to put on a bit of style, so I had rented a red Ducati ST3, the Naomi Campbell of the motorcycle world, sleek and glamorous. Ducatis are iconic bikes, as much a part of Italian identity as pasta or flirting, managing to capture on two wheels central elements of the national character: beauty, charm—and unreliability. The Sardinian coast was just the kind of place for my ST3 to strut its considerable stuff.

The island of Sardinia lies roughly equidistant from the Italian mainland and the Tunisian coast. In his classic travel book Sea and Sardinia, D.H. Lawrence described it as "lost between Europe and Africa, and belonging to nowhere." This sentiment was echoed by fortysomething Martini, who has been coming to Sardinia from Rome since she was a child. "It feels like a place apart," she said. "We always came on the ferry, and to us kids it was like arriving in a whole new land."

Her earliest memory was the sea surging against the rocks below the porch of her family's holiday villa. Now she brings her own children. "Sardinia is so much more than its glamorous coasts," she says. "They are beautiful, of course. But Sardinia, the Sardinia we knew as children, is now somewhere else. Only a few miles inland from these yachts and boutiques and smart hotels are shepherds tending sheep in the mountains. Promise me you will visit that Sardinia as well."