The most powerful street-legal single-cylinder bike is the KTM 690 SMC R, making about 74 hp from its 693 cc LC4 engine.
Power questions around big singles come up for a reason: buyers want the punch of a light machine without giving up highway pace. This guide gives a straight answer, then shows how the leading single-cylinder motorcycles stack up, what “power” really feels like on the road, and when a big single beats a twin.
Which Is The Most Powerful Single-Cylinder Bike? Answer And Context
Right now, the production, street-legal crown belongs to the LC4 family. In 2024 trim, the Husqvarna 701 Supermoto lists 55 kW (74 hp). For 2026, KTM’s own 690 SMC R technical sheet shows 79 PS (about 78 hp). Both use the same 692.7 cc single with ride-by-wire and two balance shafts. In plain terms: this platform sits at the top of the single-cylinder power heap, and the latest update nudges the peak even higher.
The track-only Ducati Supermono once claimed 75 hp from a 500–550 cc race motor, but it wasn’t sold for road plates. For riders shopping today, LC4 street models are the clear answer.
| Model | Claimed Power | Notes |
|---|---|---|
| KTM 690 SMC R (2026) | 79 PS | Latest tech sheet for the Euro 5+ update |
| Husqvarna 701 Supermoto (2024) | 55 kW / 74 hp | Same LC4 engine; street-legal |
| KTM 690 Enduro R (2026) | 79 PS | Dual-sport twin to the SMC R |
| Husqvarna 701 Enduro (2024) | 55 kW / 74 hp | Long-travel chassis; same engine |
| KTM 690 SMC R (2024) | ~74 hp | Prior tune before the 79 PS update |
| Ducati Supermono (1990s) | 75 hp | Race bike, not road legal |
| Kawasaki KLR650 (2022–) | ~40 hp | Benchmark for milder travel singles |
Main Factors That Decide “Power” On A Single
Peak horsepower sells posters. Real-world shove depends on more than one number. Here’s what changes how a single-cylinder motorcycle pulls in daily use.
Where The Peak Sits
The LC4 mill hits max power near 8,000 rpm, then signs off. Tall gearing keeps the revs in the sweet spot on fast roads. Short gearing wakes the bike up in tight city runs.
Weight And Final Drive
Shedding 10 kg can feel like gaining several horses. So can dropping one tooth on the front sprocket if your riding is mostly urban. Big singles react strongly to gearing changes because torque arrives early.
Traction, Modes, And Electronics
Cornering ABS, traction control, and slick throttle maps let you use more of the available power on sketchy surfaces. That’s why the modern LC4s feel calmer than older thumpers at the same speed.
Most Powerful Single-Cylinder Bike Models By Year
The LC4 story has stayed on top for more than a decade. Earlier 690 Dukes and SMCs sat around the low-to-mid-70s in horsepower. The 2019 engine update brought smoother manners with twin balance shafts. The latest Euro 5+ refresh pushes claimed power to 79 PS while keeping the friendly fueling riders wanted.
Which Is The Most Powerful Single-Cylinder Bike? Buying Angles
If your goal is outright punch from a single, you’re looking at the same core engine in two suits: supermoto and dual-sport. The supermoto trims run 17-inch wheels and sharper street geometry. The dual-sport trims add travel, a 21/18 wheel set, and more dirt clearance. Both deliver the same headline power; pick based on terrain and tire choice.
Street Use: SMC R And 701 Supermoto
These bikes feel alive on B-roads and city links. The short wheelbase and 17-inch rubber make quick direction changes feel natural. They also sit tall, so shorter riders may want to test the seat height in person.
Mixed Use: Enduro R And 701 Enduro
Same punch, longer legs. If your weekly loop blends gravel with tarmac, the enduro trims are the safer pick. A second wheel set with 17-inch hoops can turn one into a weekend slider without losing dirt range.
How This Guide Was Built
Top-line power quotes come from current maker pages. The 701 Supermoto lists 55 kW (74 hp) on the official site. KTM’s 2026 690 SMC R technical page lists 79 PS for the updated model. That gives a clear view of today’s power leader and the incoming bump for the same platform.
Why mention the Ducati? It shows how rare high-output singles are outside the LC4. That bike was a race special, built in tiny numbers, and not offered for road plates.
Real-World Performance: What The Numbers Miss
Power-to-weight is the headline, yet throttle response, fueling, and vibration decide whether you ride the bike hard or leave speed on the table. Modern LC4s carry twin balancers and careful mapping, so a long stint at 120 km/h feels calmer than older thumpers. The chassis also matters: a stable frame lets you open the throttle earlier out of a corner, which “adds” speed you won’t see on a spec sheet.
Gearing Choices That Change Feel
One tooth down on the front sprocket makes urban hops snappier. If you live on wide highways, keep stock gearing to drop revs. A quickshifter helps keep the single in the fat part of the curve during full-tilt runs.
Fuel Range And Heat
Big singles sip fuel when you cruise and gulp it when you wring them out. Expect a larger swing in range than on a mild twin. Heat soak in summer traffic is real; the LC4 cooling system copes well, but hand-guards and a low screen add comfort on longer days.
Power Isn’t Everything: Fit, Seat, And Reach
A tall seat and narrow saddle are part of the formula. They help with control, yet they can tire you out on long rides if the fit is wrong. If you’re under 5’8”, you may find the 701 Supermoto less friendly at low speed than a lower twin. Lowering links exist, but try a demo first.
Care And Running Costs
Service intervals on modern LC4s are generous for a high-output single. Oil changes and valve checks are straightforward once you learn the panels. Tires wear faster on supermoto trims. Budget for quality rubber; power without grip is wasted.
Safety And Rules
Power is fun, but brakes and aids keep that fun repeatable. Cornering ABS and lean-aware traction control are now standard on the high-power singles listed above. Keep the electronics on for wet days and unfamiliar roads.
Power Leaders Compared In The Real World
The table below ties power to use cases so you can pick the right tool. Most riders swing between city, backroads, and the odd highway sprint. Match the chassis to your mix and you’ll feel the claimed figures more often.
| Rider Type | Best Match | Reason |
|---|---|---|
| Urban slicer, short hops | 690 SMC R / 701 Supermoto | 17-inch wheels, quick turn-in, strong midrange |
| Gravel + tarmac mix | 690 Enduro R / 701 Enduro | Long travel, 21/18 wheels, same punch |
| Backroad weekends | Any LC4 trim | Light weight and real roll-on shove |
| Daily commute | 701 Supermoto | Tall view, flexible gearing, decent economy |
| Track days | SMC R | Brakes and chassis tuned for slicks |
| Long tours | Enduro with luggage | Room for racks, calmer at mixed speeds |
| Collecting rare kit | Ducati Supermono | Historic single; race only |
Trusted Specs You Can Check
See the maker sources here: the 701 Supermoto power spec and the 690 SMC R technical specifications.
Clear Answer
If you came here asking, “which is the most powerful single-cylinder bike?,” the answer is simple: buy the LC4 platform. Pick the KTM 690 SMC R if you live for crisp tarmac. Pick the KTM 690 Enduro R or Husqvarna 701 Enduro if your roads fade into dirt. The headline power is the same, and the ride feel you get will depend on wheels, gearing, and setup. Set it up.