I have been to southern Spain a number of times and I can suggest an alternate route.
Depending on your objective for the motorcycle riding part (seeing the sights versus enjoying the scenery and twisties), from Sevilla (while there, check out the cathedral, the Barrio and be sure to eat at the Las Teresas restaurant in the Barrio, you'll pig out on the finest Serrano ham and Manchego cheese) you could go down to Jerez de la Frontera (try a genuine arabic hammam on a side street next to the cathedral, you'll find it on Google, reservations recommended for the scrubbing and massage, quite an experience!). You could also visit the Sherry (jerez) wineries located there. Then you go on to Cadiz (endless fine sand beach on the Atlantic). From there, follow E-5/N-340 to Tarifa (windsurfing capital!), then on to Gibraltar (the Rock is worth the stop) and finally on your way back to Malaga.
The stretch of coastal road between Cadiz and Gibraltar by way of Tarifa is fairly twisty and very scenic.
The only part you'd be missing is Granada (where the Alhambra is). Your schedule permitting, from Malaga, Granada is an easy day trip there and back (approx 2.5 hrs one way). If you do make it there, visit the Alhambra in the morning (cooler) and make sure to grab lunch on the outside patio at the Parador hotel (right next to the Alhambra) for an amazing view.
In Sevilla, I stayed at the Novotel, with underground garage, 1 km from the Barrio and cathedral, you walk there. In Jerez de la Frontera I stayed at the Hipotels Hotel Sherry Park, very nice and well located near the wineries and the Royal School of Equestrian Arts (also worth a visit if you like horses). In Gibraltar (because Gibraltar proper is a zoo), I stayed just across the bay in Algeciras at the AC Hotel Algeciras, recommended.
Finally, instead of staying in Malaga, big city with a harbour, may I suggest Nerja, 45 minutes east of Malaga, a true typical Andalucian town. There is also a Parador hotel here, perched on the cliff by the sea with amazing views.
Hope this helps. Enjoy!