Small and mighty: KTM’s latest 450 SMR squeezes a feisty 62bhp from just 450cc

There’s a new KTM 450 SMR Supermoto racer on the market for 2024 and it produces a claimed 62.1bhp from a 449.9cc single-cylinder SOHC four-stroke engine and costs £11,249.

Supermoto racing is all about lightness, agility, and control – threading the needle between challenging banked and flat corners before squirting hard along short straights and over all-terrain jumps, and doing so as quickly as possible.

KTM know all about the challenging discipline, having begun production of their own 450 in 2004 and claiming the 2022 AMA Supermoto title in the USA.

62bhp is serious power for such a small single, and the impressive performance is enhanced by the fact that the whole unit weighs just 27.7kg without oil.

To put that into context, the 450 motor weighs less than some household microwaves, yet produces power on par with Kawasaki’s legendary ZXR400 four-cylinder, DOHC, 16v screamer. In fact, the whole bike weighs a claimed 107.4kg without its 7.2-litres of fuel – 77.6kg less than a Yamaha R6 Race.

But how do you squeeze so much power from one cylinder without the motor becoming a hand grenade? To find out, MCN spoke to KTM’s technical team in Austria.

“The power you get out of an engine is one thing. The other thing is the rideability,” KTM Product Manager Fabian Gusta told us. “A lot of work goes into engine mapping to find the right balance between rideability and performance. This is naturally the case for the 450 SMR, where a too urgent throttle response could easily lead to the rear wheel breaking out when accelerating.”

The basis of the SMR’s engine can be tracked back to 2013, with internal changes in the latest iteration leading to a drop in 300 grams (every little helps).

KTM’s latest weight saving measures include the use of titanium valves, redesigned engine cases, clutch, and ignition covers. Given the SMR’s impressive performance, attention has also be paid to improving oil circulation around the engine.

The internal oil scrapers (that strip off excess oil by coming close to the moving crankshaft and rods) have also been redesigned to help reduce friction, and the cylinder head has been reworked and reinforced – with new intake ports for improved air flow.

“Of course the engine is trimmed to be as light as possible,” continued Gusta. “We only use the most durable and lightweight components to achieve such a low weight. And we’ve achieved weight savings within the engine with a balancer shaft still in place, which is needed on the 450 engine due to vibration comfort.”

Finally, The engine’s position has been altered in the bike’s steel frame, which is said to make servicing easier. And that’s a good thing, as minor services are required after every 45 hours of riding and major engine-out maintenance is needed after 90 hours: jobs include changing the piston, checking the cam and valve train, replacing the camshaft seal ring, and more. This frame itself is paired with a reinforced aluminium subframe, which tips the scales at just 1.815kg.