ITS motorbikes may not be the best that India produces, in terms of performance or reliability, and they are certainly not the cheapest, but no other brand comes close to matching Royal Enfield’s cult following. Gul Panag, a Bollywood star-turned-politician, is often seen, as pictured, riding her Enfield. When she got married in 2011, her groom swept her off to their honeymoon in a Royal Enfield with sidecar.

Indeed, it is said that owning one of the bikes can improve a young Indian man’s marriage prospects. They tend to be driven by sensible types, in contrast with those who get their kicks by showing off on flashy sports bikes, such as the KTM Duke 390. Owners of Enfields lavish care and attention on them, diligently polishing each spoke on their wheels. Prospective mothers-in-law find this reassuring.

Royal Enfield claims to be the world’s oldest motorbike-maker in continuous production. Its history goes back to colonial times, when it was the Indian offshoot of a British firm. Indian-owned since the 1950s, it has long outlived its parent.

In its early days of independence it was kept going with orders from the Indian army and police, which used it to patrol rough border terrain. Now consumers drive sales: in February more than 49,000 Enfields were sold, up by 63% on a year earlier. That month there was a frisson of excitement in India’s business press when the market capitalisation of the manufacturer’s parent company, Eicher Motors, briefly overtook that of Harley-Davidson, an equally admired American bike brand, having already surpassed it by sales volume. In Delhi, enthusiasts from across the world flock to rent Enfields for rides through the Himalayas. Other bikes may be speedier on the highways and sip less fuel, but only an Enfield can survive such rugged terrain, “not your Harley-Davidsons,” sniffs one fan.

Yet as recently as 2000 the parent company was planning to close Royal Enfield down. Frequent breakdowns, oil leaks, engine seizures, electrical failures and poor service had dented the bikes’ reputation and burned much of the company’s cash. Sales were down to just 2,000 a month. A third-generation member of the family that controls the group, Siddhartha Lal—who had ridden to his own wedding on an Enfield instead of the traditional horse—persuaded his father to give him a chance to revive the brand.

Over the years Mr Lal made a number of changes to the bike without compromising on what had made it so popular. The gold piping on their petrol tanks is still painted by hand. But mechanical carburettors have been replaced with electronic fuel-injection on many models, to improve mileage and prevent breakdowns, especially at high altitudes. The cast-iron engine was replaced by an aluminium one to reduce oil leaks. When this affected the sound of the bike’s legendary “thump”, foreign consultants were called in to fix things. The thump is one of the bikes’ biggest selling-points: some buyers pay workshops to tinker with their new bikes to make it even louder.

Investment in increasing production capacity, in the firm’s southern home city of Chennai, has helped it meet surging demand, though there is a waiting-list of up to four months on some models. When their bike finally arrives, buyers sometimes hand out sweets in their workplace, as if celebrating the arrival of their first-born. K. Krishnamani, a forty-something manager at a logistics firm in Mumbai, now on his second Enfield, describes how riding his bike makes him feel as royal as the maker’s name. “On the road, anybody will stop and give way to you. That is the liberty you have when you ride Enfield.”

Correction: On March 20th this article was corrected to say that many—not "most", as originally stated—Royal Enfield models no longer have carburettors.