The single-cylinder motorcycle is where it all began. Singles represent the purest form of the internal combustion engine, yet, even by 1949, the first year of the Motorcycle World Championship (MotoGP, as we know it today), single-cylinder machines were looking a bit anachronistic.
As Kevin Cameron points out, large singles of the day were maxing out at about 7,000 rpm.
“What stops engines from revving up without limit is not piston speed, as commonly supposed,” Cameron says, “but piston acceleration. It is the violent start/stop/start yanking of piston acceleration that breaks piston rings, cracks pistons, fatigues big-end roller bearings, and fractures crankpins.”
Time to add some more pistons, so it would seem. Does that mean singles are inferior to multi-cylinder machines? No way. That would be like saying guitars are better than violins because they have more strings. The fact that manufacturers are still developing single-cylinder four-stroke technology underlines the single’s many merits: Simplicity, low weight, compact packaging, and excellent torque are why we continue to see singles powering bikes like the CBR300R, RC390, and all manner of off-road bikes. For further evidence of their thumper’s singular excellence, simply take a look at Moto3 bikes.
Singles may stand at the foot of the sportbike ladder, but there are still some amazing models out there. Here are our top picks, from the heydey of singles and today.
Yesterday: Norton Manx
There’s a reason why people still race and build Manx Nortons. The Manx is perhaps the most decorated single-cylinder racebike of all time, and arguably one of the most significant motorcycles in two-wheeled racing history. Geoff Duke became 1951 World Champion on a highly developed 500 Manx and for much of the remaining decade and beyond, the Manx appeared on many a racing grid, even as multi-cylinder machines gained the upper hand.
By the mid-’50s, according to GP pundit Michael Scott, “Norton ploughed their lone furrow a little longer with the most old-fashioned (and to some the purest) of Grand Prix racing bikes. The 500cc Manx Norton married a donkey engine with the muscles of a racehorse and had a distinctive sound. Each blip of the throttle would send the revs soaring with a staccato bark then the high-compression engine would drop almost instantly to idle.… Simplicity of design laid every function open to view.…”
The Manx’s staying power was proven once again when Mike Hailwood won the ’61 Senior TT on a 500, the final Senior TT ever won by a single. The top four machines were in fact Manx Nortons.
Today: Husqvarna 701
With a 690cc-ish engine, the Husqvarna 701 Supermoto (and the 690 Duke upon which it’s based) is one big single. With a 102mm bore, its piston would make an excellent ashtray—for a chain-smoker. For reference, the massive lugs in the 1299 Panigale’s Superquadro (Italian for oversquare) engine have a 116mm bore, but we’ll save that for another story. At 346 pounds and with 60 hp, the Husky is just asking for puerile displays of tomfoolery. Let’s face it, wheelies are only puerile if you can’t do them (insert sad face emoji).
While we can’t wait to test the 2018 Vitpilen 701, we’d also like to see a pure sportbike version using the 690 engine. Fortunately, the folks at Kramer are one step ahead of us and have built one heck of a track weapon around the 690 mill.
Have a favorite single not on this list? Let us know in the comment below.