The engine gives a motorcycle its character: how it pulls, how it sounds, how it vibrates. Here is what you need to know, from basic terms to every common layout.
The total volume of all cylinders in cubic centimetres. More cc usually means more power and torque. 125 cc is a learner bike; 650 cc is mid-size; 1000 cc+ is big and powerful.
Torque (Nm) is the pulling force you feel when you open the throttle at low revs. Horsepower (hp/kW) is how fast that force can be delivered — it decides top speed. Cruisers are torque-rich; sport bikes are horsepower-rich.
A four-stroke fires once every two crankshaft turns and has valves; it is clean and efficient. A two-stroke fires every turn, is lighter and punchier, but burns oil with fuel. Today almost all road bikes are four-strokes.
Air-cooled engines have fins and are simple and classic. Liquid-cooled engines have a radiator and coolant; they are more powerful, more stable in traffic and meet modern emission rules.
How fast the crankshaft spins. Big twins may redline at 6,000 rpm; a superbike inline-4 can scream past 14,000 rpm.
One big piston. The simplest and lightest engine, often called a "thumper" because of its pulsing sound.
Character: Punchy at low revs, vibrates at high revs.
Found in: KTM 390 DukeHonda XR650LHusqvarna 701
Two cylinders side by side. Compact and affordable — today's most popular layout for mid-size bikes. The crankshaft angle (180°, 270° or 360°) changes the sound and feel.
Character: Friendly, torquey and versatile; 270° twins sound like a V-twin.
Found in: Yamaha MT-07Kawasaki Ninja 650Honda CB500F
Two cylinders in a "V" shape. Harley-Davidson uses a narrow 45° V; Ducati uses a 90° "L-twin". A V-twin is narrow and full of torque, with the famous "potato-potato" sound.
Character: Lots of low-end torque and a deep, pulsing sound.
Found in: Harley-Davidson Sportster SDucati MonsterSuzuki SV650
Two cylinders lying flat and opposite each other, sticking out on both sides. The signature BMW engine since 1923, also used by Ural.
Character: Smooth, torquey, with a unique side-to-side rock when revved.
Found in: BMW R 1300 GSBMW R 18Ural Gear Up
Three cylinders in a row — Triumph's signature layout and the heart of the Yamaha MT-09. Many riders call it the best of both worlds.
Character: Twin-like torque at low revs, four-like rush at high revs, with a distinctive howl.
Found in: Triumph Street TripleYamaha MT-09MV Agusta Brutale 800
Four cylinders in a row across the frame. The classic layout of Japanese bikes since the Honda CB750 (1969). Smooth, powerful and loves high revs.
Character: Silky smooth, builds power to a screaming top end.
Found in: Kawasaki Z900Yamaha R1BMW S 1000 RR
Four cylinders in two banks forming a "V". A MotoGP-style engine: as powerful as an inline-4 but narrower and with a stronger mid-range.
Character: Racing power with a deep, aggressive roar.
Found in: Ducati Panigale V4Aprilia RSV4Honda VFR800F
Rare and luxurious. Honda Gold Wing uses a flat-six (boxer-style); BMW K 1600 uses an inline-six. Found on premium touring bikes.
Character: Turbine-like smoothness and effortless pull.
Found in: Honda Gold Wing (flat-6)BMW K 1600 GT (inline-6)
Fires every crankshaft turn and has no valves, so it is very light and punchy. Almost gone from the street because of emissions, it lives on in enduro, motocross and trial — now often with fuel injection.
Character: Explosive "powerband" hit, crisp and raw.
Found in: KTM 300 EXCYamaha YZ125Beta RR 300
No pistons at all: a battery powers an electric motor. Maximum torque from 0 rpm, usually no clutch and no gears.
Character: Silent, instant, linear acceleration.
Found in: Zero SR/FLiveWire OneKawasaki Ninja e-1