BETA LAUNCHES EVO 2009 TRIALS RANGE

Everything turnes around the new frame, a single-beam aluminium chassis which simultaneously provides maximum rigidity and reduced weight, meanwhile representing the bike’s bone-structure and functioning as its fueltank.

Another important change, which development has required a long time, a weight shift towards the bike’s centre of gravity, raising it at the same time, in order to improve the bike’s dynamic behaviour. Here, too, the results were striking.

The redesigned cycle parts strongly contributes to improve riding feeling. Key element is in this case is the shockabsorber with progressive linkage, to centre the masses along the EVO’s longitudinal and transverse axes.

A completely new bodywork, designed paying particular attention to ergonomics and to overall dimensions reduction, is another important peculiarity.

The 2-stroke engine’s 290cc capacity is an absolute novelty, as well as its positioning in the frame, being allocated higher than in any of its 2-stroke or 4-stroke predecessors.

The 2-stroke engines are equipped with a dismantlable cylinder head, a new generator with dual mapping and a new exhaust system with an expansion box first chamber.

The 4-stroke engines are equipped with a dual mapping control unit and a new exhaust system with a three-chamber mechanical silencer to combine performance with reduced noise output.

TECHNICAL INNOVATIONS

Cycle parts
The innovative character of the single-beam aluminium frame, with its integrated fueltank, is clear from the design configuration, based on a principal beam formed by extrusion. That houses the fuel supply, with forged cross-pieces front and rear completing the structure.
This conformation enables us to make optimum use of metal thicknesses and sections at points of maximum stress (finite element analysis was used for the frame calculations). This also allows us to achieve our targets in terms of lightness, rigidity and compactness.
The 38 mm forks are also new. They are the result of exclusive joint development by Beta and Paioli. The redesigned fork inner components are distinguished by the extensive use of light alloys and by sophisticated management of extreme hydraulic effects (damping). This is all fitted into a very light and compact design, with a 600 gram saving in weight. The result is a smoother and more progressive operation compared to any front suspension we have used in the past.

An important and characteristic feature is the super-light aluminium fork yoke, 150 grams lighter than in the past, fitted with pivoting single-fixing handlebar risers for easy and quick maintenance.
The EVO’s wheels have been lightened, with new aluminium spoke-nipples, and lightened wheel-spindles fitted with more compact wheel bearings.
Another new component is the aluminium swing-arm, which works by means of a progressive leverage system. This important element was designed by Beta’s R&D department, using extruded and hydroformed rails. This is a process which shapes the part by water-pressure, with a view in this case to correct distribution of thicknesses so as to limit weight and increase rigidity.
We have already mentioned the new monoshock with aluminium body. We should add that it has adjustments for spring preload and rebound damping.
The rear brake system has been designed from scratch for EVO. The object was to reduce bulk and weight, at the same time increasing braking efficiency and precision. The rear master cylinder and its mounting to the frame are new, as is the caliper and its fixing system to the swing-arm. Furthermore, both the 160 mm diameter disc and the brake pedal are new.
The engine protection plate is more rigid than in the past thanks to the insertion of reinforcing platelets between the frame forgings and the plate itself, the most stressed point.
The electrical wiring system has been completely revised.
The radiator is the result of fresh research. It now uses a different coolant circulation layout, designed to ensure greater cooling efficiency. It has a new temperature sensor, directly mounted on the radiator.
The air filter box also is based on a novel design concept, aimed at minimising pressure drops on the intake stroke and so maximising performance.

Engine

· The choice of 290cc cylinder capacity was dictated by the search for greater versatility in use, to satisfy both competition riders’ need of performance and leisure riders’ request for more power and torque at low revs.

The power plant is located noticeably higher than in our earlier models, because of the benefits this brings to the bike’s dynamic behaviour by optimising the position of the centre of gravity.

· The generator with its external pickup is new, with a higher power output and a programmable control unit with dual mapping (soft and racing) selectable by means of a switch.

·         The ignition casing has also been reshaped to accommodate the new ignition components.

·         The combustion components have been redesigned: the cylinder head can be dismantled into two pieces.

·         The conrod and the new piston are forged. Result: 30% less weight, to reduce reciprocating masses, and a noticeable reduction in engine vibration.

·         Finally, the exhaust system has been reconfigured to feature an expansion chamber which combines better performance with an audible reduction in noise output.

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