Mr Lockett (48), a flooring contractor, was reported missing on December 31 and found dead the next day.
An inquest was held in Queenstown in April.
Mr Crerar, in finding Mr Lockett died between December 30 and 31 on State Highway 8, 7km north of Kingston, said he had lost control of the motorcycle he was driving "due to a combination of an excess blood-alcohol concentration, inexperience and mechanical defect".
The motorcycle left the road on a moderately sweeping right-hand bend, struck a rock and came to rest on a grassed area.
The cause of death was consistent with acute respiratory failure, due to a severe impact to the chest.
Pathologist Han-Seung Yoon said Mr Lockett's death was "unlikely to be instantaneous" as he had no major head injuries.
"He might have lost consciousness, but must have survived for some interval and eventually died due to respiratory failure."
Mr Lockett's blood alcohol level was 44mg of alcohol per 100 millilitres of blood.
Mr Crerar commended Kingston Hotel management, who took Mr Lockett's car keys from him in an attempt to stop him driving.
"It was no fault of theirs that [Mr] Lockett . . . chose to ride his motorcycle, probably whilst intoxicated."
An inspection of his Harley Davidson motorcycle found the front service brake was not operating.
Alexandra Serious Crash Unit Advanced Crash Investigator Constable Alastair Crossland found Mr Lockett was travelling about 100kmh at the time he lost control and between 64kmh and 75kmh when the motorcycle hit the rock.
Mr Crerar said Mr Lockett had never applied for a motorcycle licence and had ridden the motorcycle only 187km in the previous five months.
