A man who was thrown from his dirt bike in Melbourne’s south-eastern suburbs lost consciousness and died while on the phone to a triple-0 operator.

The man was riding in a Hampton Park reserve when he came off the bike, which landed on him, around 8.30 last night.

He called for help but lost consciousness while speaking to the operator.

Emergency services found the rider and commenced CPR, but he died at the scene.

Meanwhile, a 25-year-old man has been charged over the hit-and-run collision on Friday that left a teenage cyclist with life-threatening injuries in West Melbourne.

Ben Tyrrell remains in a coma in hospital.

The driver of a Jeep 4WD handed himself in to police and has been charged with failing to stop and two other offences and was bailed to appear in court on Tuesday.

The cyclist, Ben Tyrrell,18, suffered serious head injuries and remains in a critical condition in Royal Melbourne Hospital.

Mr Tyrrell, from Cloverlea in Gippsland, was hit by the Jeep while cycling near the intersection of Dryburgh Street and Dynon Road in West Melbourne just before 1am on Friday.

Police said a person travelling in the car that hit the cyclist got out of the vehicle before getting back in and driving away without going to the injured man’s aid.