O Features archive - January 08
O Picking up the vibes
Feel the vibes, man...
…or at least something like it, was a line in Kelly’s Heroes uttered by Donald Sutherland’s character. CBG’s character, Jim Reynolds, tells of his own vibes.
We all know that British parallel twins vibrate, to state the blindingly obvious. Which doesn’t mean that the type is not easy to live with and a pleasure to ride, or that the inherent disadvantage of the layout has ever stopped it succeeding in competition, from the relatively gentle art of trials to the extreme of taking the World Motorcycle Land Speed Record.
Just as there are theorists who will tell you that a bumblebee simply cannot fly because it doesn’t comply with whatever rules of physics they are blindly applying, those who would dismiss the most common form of twin built in this country overlook the fact that it sold in many thousands and a lot of them are still out there, happily buzzing along and clocking up the miles.
Manufacturers addressed or ignored the vibration problem in a variety of ways. Triumph coined the phrase ‘The Triumph Tingle’ in a gesture of pure kidology, while Royal Enfield took a more serious approach and had the cranks of their bigger twins dynamically balanced, to earn a grudging reputation for making a pretty smooth bike as a result.
BSA, to my knowledge, carried on building the 500 and 650cc twins without publicly acknowledging that there was a problem, and indeed there wasn’t for them, as their output was readily sold in the 1950s and on into the 60s and early 70s. Down in London, AJS and Matchless told the world that their unique three-bearing crank dealt with the problem, and it seems that most of the world believed them, whatever else actual experience suggested.
Norton were like the rest; they knew the man in the street accepted vibration, from single or twin cylinder models, and ignored it. Not that the better informed didn’t know about it. Works racer Harold Daniell, who set an Isle of Man TT 91mph lap record in 1938 that stood until 1950, was quoted in later years saying about one of the revered 500cc Manx models when it was revving hard: “I’m not sure which of those three handlebars I’m supposed to hold.” Definitely not out of the PR-aware bottom kissing mould was Harold, and the world laughed when they heard his words and realised that even the Gods of Speed had to live with the industry’s products shaking a bit.
There are reportedly other advantages, as a young lady explained to me many years ago when she asked: “Who needs a man when there’s the vibration of a British bike?” but let’s not go there… vibration, or the acceptance of same, seems to have satisfied most needs. Whoops, sorry I said that.
Then Norton launched the Commando in 1967 and hardened road testers reported that this was a bike that didn’t vibrate. Well… it actually shook like a good ’un, but the ingenious Isolastic rubber mounting system of engine and transmission was insulating the rider from the effect. Ride Norton’s Featherbed-framed 750cc Atlas and then the rubber insulated (isolated?) Commando with fundamentally the same power unit if you want to appreciate the difference in rider comfort the two types offer. Chalk and cheese, believe me. So why should they bother to try to make the inherently vibratory twin smoother running?
- End of online sample -
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