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Brit benchmark

royal enfield Model KX

1937 Royal Enfield Model KX

Rare, fast, and very desirable, Royal Enfield's premium 1140 V-twin of the 1930s is still a great ride

(Feb 2024, Guy 'Guido' Allen, pics by Aaron Puls & GA)

royal enfield model kx

Stumbling into owner Phillip White's shed, you're confronted with a long, low and elegant Brit V-twin, the lines of which are unmistakably 1930s Art Deco. That in itself is reason enough to visit.

royal enfield model kx

By Phillip's reckoning, it's one of around 70 of this series surviving world-wide, and one of a batch of just three KX imported into Australia by a Brisbane dealer when new.  The upmarket KX, by the way, was distinguished from the K by more elaborate finish that incorporated chrome panels, and interchangeable wheels.

Why so rare? They cost a bomb when new and reached their zenith moments before the outbreak of World War II. When hostilities ceased, the British home market went through a long period of austerity. That in turn meant Royal Enfield wasn't in a position to fund the development of a new generation of an elite platform.

royal enfield model kx

"These vehicles were designed at the very twilight of the era of the side-valve V-twin," Phillip explains. "They have something going for them that earlier side-valves don't, which is they are a complete design. They're not a bunch of parts traveling in close formation. And they're not a boring hack  – they were designed to be pursuit bikes.

"They were timed at 85mph (140km/h) when new, though obviously it's happier at 55mph (90km/h). But it's freeway capable, as you're about to find out. Ride it like you stole it."

royal enfield model kx

If you take the time to go over the machine, you can see what Phillip means by a complete design. Rather than buy a proprietary engine from JAP or the like, Royal Enfield went to the trouble and expense of drafting the powerplant from scratch.

royal enfield model kx

Displacing 1140cc, it's a 50-degree dry-sump V-twin running 5:1 compression. The engine cases incorporate a giant 8-pint (4.5lt) oil tank at the front, which aids cooling, and somewhere in the architecture are four oil pumps. It has no oil rings – it smokes on start-up but clears soon enough.

royal enfield model kx

The transmission is four-speed with hand change and the option of foot- or hand-operated clutch. This machine originally came with a foot clutch but Phillip has since converted it to a left-hand lever. The hand-shifter remains on the right.

royal enfield model kx

Phillip points out the inherent strength incorporated into the chassis, including the frame and  forks. While the front suspension looks like a set of Bramptons, they are in fact Enfield's own more robust design. Phillip is a fan of them, saying, "I once hit a metre-wide down-to-the-dirt memorial to our Premier (pothole) while doing over 80km/h and immediately assumed I was toast. The old monster just crashed into the hole and out again with nary a shake of its elderly head!"

The rear end is a hardtail, with a well-suspended rider seat. Braking is by 8-inch mechanical drums at both ends.

The controls are straight-forward for the period and include a manual retard/advance lever for the ignition.

royal enfield model kx

I'll admit to some trepidation at the idea taking this thing out in Melbourne inner city traffic and then on to the nearby freeway, knowing how much effort Phillip had sunk into the restoration. However he promised muggins would be surprised at how easy it would be to handle. And he was right. Compared to something like the 1947 Indian that was in the shed a while ago, it was a breeze.

Phillip's restoration had included some subtle re-engineering where needed, such as fitting a belt primary drive and establishing a light and predictable clutch.

royal enfield model kx

Threading through the traffic proved to be far less traumatic than I anticipated.

Out on the freeway, it simply loafed along and seemed perfectly happy at 60-65mph (100-110km/h). It steered better than I expected – quite neutral – and handled the odd bump without fuss.

royal enfield 1937 KX

Like a lot of older machinery, you needed to allow it extra space to do everything, such as stopping, finding the gear you want, and so-on. That said, it was easily the most enjoyable and benign ride I've had on anything built prior to 1955. Amazing.

royal enfield model kx

Phillip (above) reckons this has been the machine he turns to when one of his post-war classics spits the dummy, as it always starts and runs reliably. I believe him.

royal enfield kx

That brief experience had me thinking this would be a really interesting alternative to a Vincent twin, and as enjoyable.

Phillip is looking at new projects and the KX is on the market at Au$60,000 (US$39,000, GB£31,000). Contact the owner by email.


K/KX owner site

See Royal Enfield's 2018 homage to the KX

royal enfield 1937 KX


More features here

See the bikes in our shed


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