Hydrogen-gasoline dual-fuelled internal combustion engines (ICEs) have emerged as a viable alternative to conventional gasoline engines, promising reduced emissions and improved fuel efficiency. The integration of hydrogen as a supplementary fuel in naturally aspirated engines, however, introduces a critical challenge that affects engine performance. Nevertheless, it also introduces significant security challenges, notably the increased risk of backfire within the intake manifold. This study investigates the security issues associated with hydrogen-gasoline dual-fuel engines, with a particular focus on the propensity for intake manifold backfire due to the presence of hydrogen. Through experimental analysis and simulations, the study explores various techniques to eliminate or reduce the occurrence of backfire. These techniques include optimized fuel injection timing and camshaft modification. The results of the simulation show how the modifications affect the basic characteristics of the natural aspirated internal combustion engine.