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The Drysdale 750-V8 was featured on the 'Australian Motorcycle News' stand at the Phillip Island World Superbike Championship Expo in April 1999. The bike attracted plenty of attention, showing off it's new fuel injection system and other developments. |
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Work is currently focussed on the development of a fuel injection system
and this is now well advanced. Rotary barrell throttle bodies (similar
to those used in F-1) have been designed and constructed by Drysdale
specifically for the job, consisting of a cast housing with a one-piece
rotating spool inside. The spool is cross-bored so that at full throttle
it's bores come into alignment with those of the housing, giving a perfectly
smooth intake tract unencumbered by any throttle butterfly, slide, needle
or similar obstruction. More details and photos of these throttle
bodies will be online soon.
The control unit for the injection system will be supplied by MOTEC and the injectors by BOSCH. This system will be a full Engine Management System (EMS) and as such will take care of ignition duties also, meaning the Vance and Hines ignition system will no longer be required. Pictured here are the new throttle bodies and delicious array of inlet trumpets for the system. |
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A sculptured alloy fuel tank was constructed to extend from the very rear of the bike, under the riders seat and up over the engine almost to the triple clamp. The total capacity is 20 litres and utilises an external fuel pump. A large diameter tube links the two high points of the tank allowing quick filling from one point as required by endurance racing regulations. |
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Extensive wind tunnel testing with various ducting configurations revealed there was insufficient airflow to the underseat radiator to cool the engine as the power output increased with development- a result of the engine being wider and taller than other bikes using a similar style radiator. Therefore it became necessary to reposition the underseat radiator to a more conventional front mounted position. The new configuration incorporates high and low radiators piped together in parallel delivering excellent cooling even in the unusually high temperatures experienced in Australia recently. |
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The original CV Mikuni carburetors used in initial testing were replaced by 32mm Keihin FCR flatslides, a tight squeeze (1mm between the caps) but well and truly worthwhile! The reaction of the V8 to these carbs confirmed their reputation as the best motorcycle carburetors in the world! They were not without their drawbacks however, including a very heavy throttle action and a relatively large investment of time for small tuning changes. |