One of the big attractions of classic bikes has always been the variety of sounds they produce; as modern bikes have become more heavily silenced, the distinctive sound quality of past machines has gained ever more appeal. And if the future is electric, modern bikes will become even quieter!
The steady heartbeat of a classic four-stroke single with a big flywheel, a ‘thumper’, can provide a relaxing rhythm for mile after mile, as though the machine were a living companion for the rider. When tuned for racing and endowed with a huge megaphone exhaust, the sound changes to a much sharper bark under load, followed by a thunderous bellow with the throttle closed on the overrun.
Parallel twins inevitably sound busier than singles at a given road speed, with a characteristic snarl as the revs climb. Compared to singles they have a greater appetite for revs, responding more crisply when the throttle is blipped during a downshift. You may not be going faster on a twin than a single, but it will probably feel like you are!
If singles and twins sound distinctive, triples conjure up the full orchestra. Sharing some of their aural signature with six- and twelve-cylinder engines gives triples a head start in the sound rankings. A racing BSA/Triumph or MV triple, pulling away from a standstill to full speed, starts with a rumble which builds to a roar in the mid-range and tops out into a haunting wail at maximum revs.
Once a rarity among bikes, the four cylinder engine became commonplace following the domination of the market by Japanese manufacturers. By the 1980s it seemed as though every other bike that went by was sporting a howling aftermarket 4 into 1 exhaust to replace the near-silent original. Ironically, with many such bikes now worthy classics, the increasingly rare original systems are highly sought after!
For some enthusiasts the top classic sound comes from a six, preferably one of the legendary Honda GP sixes of the 1960s. What other machines prompt people to travel hundreds of miles to hear one being paraded or make grown men weep with joy at the sound? The soprano song of the Hondas is a full octave higher than the four cylinder bikes when parading together.
In the V-twin camp, Harley-Davidson tried unsuccessfully to register the distinctive ‘potato-potato’ sound track of their iconic 45 degree twins as a trademark, in the face of growing competition. More sporting machines from Italy with 90 degree vees have an altogether more business-like, but still thunderous, sound track.
Two-strokes divide opinion. Many bike fans who were teenagers in the 70s or 80s will tell you wistfully that nothing propels them back to their youth so instantly as the crackle of a stroker firing up. However, ask someone who spent time in the club race paddocks of the 70s and they’ll probably just say ‘pardon?’ because hearing damage was a real issue before silencers were fitted to racing 2-strokes.
What’s your favourite classic bike sound? Let us know in the comments below.