Big, single-cylinder engines have always been a bit of a rarity on the market. While the single-pot layout was a rather popular one for sub-400cc bikes throughout the years, you would rarely see the cylinder reach a displacement of more than 500cc—with a few exceptions of course.
Nowadays, most manufacturers tend to opt for more efficient two or four-cylinder units, leaving mainly dirt bikes to hold the “mono” fort.
There is, however, a handful of 500cc-plus modern and road-legal models that defy the odds and continue to rock a single thumper. If you like the... unparalleled feel and character of a mono-cylinder, you might want to check these models out.
Husqvarna 701 Vitpilen and Svartpilen
The Black and Silver Arrow go hand in hand. Under the sheet metal, they’re virtually the same bikes. It all comes down to where your personal preference lies between the flat-track and the minimalistic café racer aesthetics.
The Vitpilen and Svartpilen, alongside the Supermoto and their KTM 690 counterparts, run on one of the biggest single-cylinder engine currently in production: a 693cc, liquid-cooled, four-stroke unit rated at 75 horsepower and 53 lb-ft of torque. The cylinder has a 105-mm bore and an 80-mm stroke and it’s teamed with a six-speed gearbox.
The two Arrows sound absolutely delightful and they are devilishly fun the ride on—provided you don’t have to cruise at highway speeds for too long.
KTM 690 Enduro R and SMC R
Team Orange’s take on the big single resulted in the 690 Enduro R dual-sport and SMC R supermotard. Like the Husqvarna 701s, both 690s are built on the same chassis and use the same engine, with the Enduro set up to tackle the trails while the SMC is the freak in the street.
The engine is the same one used by Husqvarna, the 693cc, liquid-cooled, four-stroke single with assist slipper clutch and six-speed transmission. The power figures are also the same across the board with an output rated at 75 horsepower (KTM doesn't disclose the torque figures but we can assume it’s similar to the Huskies’).
The Suzuki DR 650 might not be the famous Dr Big, but it’s close enough. Call it Dr Big’s little brother, if you will, with the only exception that the 650 is still around (and virtually unchanged) unlike the DR 750-turned-800 that was pulled from the market before the turn of the millennium. This middleweight DR has been around for 30 years now after replacing the 600 in Suzuki’s dual-sport lineup in the early 90s.
The DR 650 runs on a 644cc, four-stroke, air-cooled single with a 100mm bore and 82mm stroke. It's paired with a single, Mikuni carburetor, and a five-speed transmission—talk about old school!
Don’t get too excited, we cheated a little bit with this one. There is no 2020 model-year for the KLR650—in fact, Kawasaki officially stopped producing the bike after 2018. To this day, however, it remains listed on the company’s website so, who knows, maybe there is one left in a dark corner in a dealer somewhere. That's provided you don’t mind buying a new old bike. Or is it old new?
The KLR has been a popular model in the dual-sport segment and is considered by many to be a Swiss-army knife kind of bike. It uses a 651cc single-cylinder thumper with a bore and stroke of 100mm x 83mm and a five-gear transmission. Like the DR, the KLR is also carbureted, using a Keihin CVK40 unit, except it is liquid-cooled which is slightly less old-fashioned than the Suzuki. The model was introduced in 1987 and despite a thorough overhaul in 2008, it also remains virtually unchanged.
Just like Suzuki and Kawasaki, Honda also has a dual-sport 650 that’s been around since the dinosaur era. The Honda XR650L leans further on the “dirtbike” end of the spectrum than its competitors but remains part of the dual-sport portfolio nonetheless.
The premise of the XR is the same as the other aging but straightforward adventurers on this list: you get a rugged, big cylinder—644cc in this case—that has stood the test of time, tucked inside a bike that doesn’t need to prove itself anymore. Carbs and five-speed gearbox included.
Royal Enfield Classic and Bullet 500
All the Royal Enfields currently on the market run on a single-cylinder engine except for the Twins introduced in 2019, the Continental GT and the Interceptor. If you want the mono flavor, as good as the Twins look, you might want to check out the Classic or the Bullet with their 500 (ok, fine, 499cc) thumpers. The half-liter pot has a bore of 84mm and a stroke of 90mm and produces 27 horsepower and roughly 30 lb-ft of torque.
Like the KTMs and Husqvarnas, the Royal Enfields have “modernized” engines with electronic fuel injection instead of carbs—don’t be fooled by their delightfully vintage looks.