A 45-year-old Japanese national was badly injured when the motorcycle he was riding crashed along a sharp curve of Kamehameha Highway near Crouching Lion Inn in Kaaawa about 10:25 a.m. today.

No other vehicles were involved, but traffic was contraflowed for several hours as officers investigated the scene.

Police initially reported the man as being taken to Queen’s Medical Center in critical condition. A spokesman for the city Department of Emergency Services said he was upgraded to serious and stable on the way the way to the hospital.

The man was driving a 2001 Harley Davidson northbound on an uphill left turn just past Crouching Lion when he lost control and hit a guardrail, police said He was thrown from the motorcycle and sustained severe injuries.

The victim was not wearing a helmet.