With the sport of karting celebrating its 50th birthday in 2006, it seemed an interesting exercise to pit a kart from the earlier days of the sport against its contemporary counterpart to see what progress has been made in kart development in recent decades. Using the driving services of Buckmore Park Kart Shop co-owner David Catt, a fully restored Sisley Kestrel/TKM FF99TT 100 National, circa 1978, and a 2005 Tonykart Venox UK Rotax MAX outfit were assembled at Buckmore Park for a back to back test session to establish what conclusions might be drawn from nearly 30 years of development. When the Kestrel kart was new, 100 National was the backbone of British karting, the Rotax MAX of its day.
Manufactured in large volumes by Bill Sisley’s Sisley Karting empire, some 2,500 Kestrels were sold during a ten year period from the early seventies into the eighties. While Johnny Herbert is of course the most notably successful driver who campaigned in one of these karts (to win the 1979 British Junior Championship) the Kestrel kart, over a ten year period, achieved ten outright British Championship wins campaigned by drivers such as Tim Davey, Tim Harvey, Lee Cranmer, Wayne Homer, Gary Prior, John and Richard Weatherly and Mark Tredwell among others. While the Kestrel is powered by a late ‘70s aircooled TKM FF99TT rotary valve producing approximately 19bhp and runs on rock hard, skinny Goodyear Blue Streak tyres, the Tonykart we used, kindly loaned by The Kart Shop, featured the hugely popular water-cooled Rotax FR125 MAX engine producing around 28bhp and running on Vega SL7 tyres. The karts look completely different. The Kestrel with no bodywork looks very narrow, especially on the skinny tyres, and while the Tonykart sports a 12mm disc and 50mm axle, these components on the older kart are exactly half these dimensions. The Tonykart subsequently looks a lot more aggressive with its liveried bodywork and fatter tyres. Out on the track, the Kestrel proved to be something of a surprise. Despite being some 3 seconds slower than the Tonykart, the whole experience was a lot more raw and exciting. You really felt part of the kart. Despite a lack of grip compared to the modern machinery, the Kestrel was superbly balanced and very predictable, especially on the downhill section of the circuit.
The Tonykart by comparison was very refined and because of the engine’s watercooling, more sophisticated exhaust and rev limiter, was a lot quieter. The kart drove with a precision that was missing in the Kestrel and was a lot easier to place on the track thanks to the superior grip. The engine is a completely different animal but provides strong performance through the entire rev range, the ‘70s motor being far more peaky with a narrower power band. David ran the older kart very rich and was also wary not to place too much stress on the brakes and the tyres but he reckoned by leaning the motor off, becoming more acquainted with the Kestrel and replacing the 25 year old tyres with something newer, it would easily be possible to get within a second of the modern kart’s times. The easiest way to contrast the experience would be to liken it to driving a 1973 Porsche 911 and a 2005 model. Both provide excellent fun and driving pleasure, the earlier example air-cooled and more crude but lighter and perhaps more sensational while the newer model does the same thing but with more finesse, precision and refinement. Whether that is to the detriment of the overall driving experience will always be up for debate.