MR Maidin Hussien was on his way to work last Monday morning when his motorcycle sputtered to a stop, its fuel gauge on empty. It didn't take the 43-year-old long to realise what the problem was: for the third time in the last seven months, his Honda Phantom had fallen victim to petrol thieves.

Mr Maidin, who reported the theft to the police, was not the only victim to file a complaint that day.

Another man in his early 30s who parked his motorcycle at a multi-storey carpark at Senja Road in Bukit Panjang also discovered $15 worth of petrol stolen.

Mechanics who spoke to The Straits Times said taking petrol from a motorcycle is not complicated, especially for older models whose fuel pipes are vulnerable.

Some newer models, such as the Yamaha R6 and Suzuki GSXR, make the process a little harder, but can still be pillaged, said Mr Thamo, 34, owner of motorcycle repair shop Bikelab along Serangoon Road.

There are various alarm systems - costing about $300 to $500 - which can be installed in motorbikes. The more expensive perimeter alarms use sensors which sound an alarm if someone gets too close. Vibration alarms are triggered when the bike is shaken or moved.

Also vulnerable to fuel thefts are heavy vehicles like trucks and lorries, which have exposed fuel tanks too.

Police said there were 96 reported cases of diesel stolen from heavy vehicles last year. They do not have statistics on petrol theft cases.