Pasolini's motorcycle lurched sideways and crashed into the guardrail, killing him instantly. Pasolini's motorcycle then bounced back onto the circuit and struck Saarinen on his head. The impact knocked off his helmet and he sustained fatal head injuries. The collision caused a chain reaction accident in which more than 14 riders were involved including; Hideo Kanaya, Walter Villa, Victor Palomo, Fosco Giansanti, Börje Jansson and Chas Mortimer with several of them suffering serious injuries. The race was stopped and the following 500cc race was cancelled in the aftermath of the accident. Over the years, the cause of the accident was the subject to significant controversy. The original cause of the crash was attributed to a spill left on the track during the 350cc race when Walter Villa's Benelli began smoking and leaking oil on the penultimate lap. Race officials failed to remove the spillage prior to the 250cc race, and one rider, John Dodds, made his concerns known to authorities, only to meet with threats of ejection from the circuit by police. However, some articles have appeared showing photos of Pasolini's bike consistent with engine seizure, locking the rear wheel and causing the crash. Further the official inquiry into the accident, issued in September 1973 found that the cause of the accident was the seizure of the engine in the motorcycle of Renzo Pasolini. Legacy The tragedy at Monza was a shock to the motorcycle racing community. Two of the sports best riders had been lost and the factory racing teams of Suzuki, MV Agusta, Harley Davidson, and Yamaha joined together to demand safer conditions at race tracks. Only forty days later, three riders in an Italian Juniors race were killed in the same turn. One month after the Nations Grand Prix, race teams took a stand and boycotted the Yugoslavian Grand Prix held at the treacherous Opatija Circuit due to dangerous track conditions. The Yamaha factory went further by withdrawing from racing for the rest of the year to honor Saarinen's memory. The death of Gilberto Parlotti at the 1972 Isle of Man TT and the deaths of Saarinen and Pasolini in 1973 highlighted the need for improved safety standards for motorcycle racers. At the time, many motorcycle Grand Prix races were still being held on street circuits with hazards such as telephone poles and railroad crossings. Dedicated race tracks of the time were also dangerous for motorcycle racers