Reasons why motorbikes can spontaneously combust

The fire at the Carina apartment building (HCMC) caused great damage to people and property. The initial cause was determined to be a spark from a SYM Attila scooter. The cause of the spontaneous combustion remains unknown, and there has been no conclusion from the authorities. According to motorcycle technical experts, parked motorcycles rarely spontaneously combust, but there are still rare cases.

Mr. Le Hoai Sam, chief technician of a Piaggio dealership, said that the vehicle did not start but caught fire most likely due to an electrical short circuit. A short circuit is a phenomenon in which the positive and negative poles of the power source come into direct contact with each other without passing through a power consuming object (resistor). The positive wire of the battery comes into contact with the vehicle frame, heating up the wire and contacts, which in turn causes the wire casing to burn and spread to the plastic part.

The fire at Carina apartment building was initially determined to be caused by sparks from an Attila motorbike.

This phenomenon often occurs with older cars, during the repair process, not carefully reassembled, leading to exposed wires. Or the wire cover after long-term use can be degraded, crumbling, from which it is easy to contact the car frame, causing a short circuit and fire. The first part to burn is the wire and it takes a long time for the cover to burn.

In particular, during the repair process, the vehicle may have to replace the fuse, but this type is not of the correct specification, does not operate properly when there is an electrical short circuit, leading to the risk of fire. For new vehicles, the fuse system is better, because it is divided into many points. In the event of an electrical short circuit, the fuse in that area will be cut off immediately, minimizing the spread to neighboring areas, limiting the risk of fire.

Mr. Do Manh Hung, a technical expert at Honda Vietnam, has a similar opinion. “Normally, when the key is turned off, the battery and the wire to the keyhole still have electricity but through the fuse. If there is a short circuit, the fuse will blow, but if the fuse is replaced incorrectly or additional equipment is installed incorrectly, a fire or explosion can still occur,” said this expert.

Fuel injection technology also affects the possibility of spontaneous ignition, depending on whether the vehicle uses a carburetor or electronic fuel injection. According to a motorcycle expert, if the vehicle is very old and uses a conventional carburetor, the level of ignition when there is a spark will be easier and more dangerous. Newer vehicles using electronic fuel injection are less likely to have fuel leaks.

Experts also shared that cars with accessories such as anti-theft devices can also catch fire. Many times, the incident occurs because the installer is not careful at the joints and windings, causing the ground wire to come into contact with the ground wire, causing a sudden short circuit, leading to the risk of fire.

Users should maintain their vehicles at reputable, authorized dealers. Because large dealers have more control over the repair and maintenance process, ensuring higher safety. However, in engineering, there are also unavoidable objective accidents such as rats biting wires or the wire cover deteriorating over time, leading to contact with the car frame and short circuit.

In the past, there have been many cases of motorbikes spontaneously combusting, all while they were on the road. The SYM Attila line itself has also recorded a phenomenon where the connection between the battery, charger and trunk light was burned by the motor, causing the plastic and rubber connection to burn, and the entire wiring system on the right side to melt.