HAS BMW lost the plot? Like a cardigan-wearing Dad who now wears hoodies, and swaps Val Doonican LPs for iPod downloads, the revered German motorcycle maker has gone funky with the HP2 Enduro, the most powerful off-roader on the market.

The machine is centre stage on BMW’s stand at the International Motorcycle and Scooter Show that opens this weekend at the NEC in Birmingham.

But after decades of building some of the best, most reliable, though possibly dull, motorway cruising machinery, will BMW come to rue trying to bolster its “street cred” image with the bizarre HP2?

The HP2 (High Performance with two cylinders) is a monster. My son’s off-roader is a 125cc Yamaha two stroke. It weighs only 80kg, but fall off in the mud and it is a pig to pick up. The HP2 is a 1170cc machine that weighs closer to 200kg. Drop this thing off-road and a slipped disc awaits.

The bike’s chassis was bred by BMW racers on the gruelling Paris-Dakar race. There are some great touches, like a spirit level built into the frame so that you can get the suspension settings just right and an air rear “spring” that you can deflate or pump up via a valve, to adjust the suspension to suit your riding and the terrain.

The nobbly off-road tyres, especially in a day of driving rain and leaf-strewn roads, give a lot more grip on tarmac than you might think at first sight.

To get the best out of the bike you need to sit forward on the saddle, allowing you to wrestle the bars and to lean in through corners, and to fight the huge wind blast at motorway speeds, because of those wide bars, lack of fairing and upright seating position.

It is an incredibly tall machine and any rider under six foot could have trouble getting both feet on the ground. The twin-cylinder engine sounds great, it looks mean and strong, and though at a tad under £12,000 it is expensive, it will also be exclusive as BMW plans to limit the numbers built and restrict supply.

In truth, apart from out-and-out racers who will campaign the bike in events like the Baja off-road races in California, most HP2s — like their four-wheel drive car equivalents — will rarely venture off road despite the machine’s mud-beating talents. The bike has the ability — but will the owners?