Established in 1989, Nova Racing is one of the few companies to supply racing gearboxes to British Superbike teams.
At its factory in Partridge Green, West Sussex, two vibratory-bowl finishing machines are used to polish most of the gears and shafts after they have been machined and hardened, using a process known as super-finishing.
Superbike racing features what are essentially standard production motorcycles — albeit highly modified — as opposed to MotoGP, which uses purpose-built motorcycles. For a Superbike to be eligible to race, it must maintain the same overall appearance as its road-going counter-part, so the frame cannot be modified but elements within it may be, including the gearbox.
Nova director Sean Whittaker says: “The major production bike manufacturers have their own racing divisions for upgrading their products for road and track racing. However, they tend to charge a lot, supply can be intermittent, and the parts are not necessarily optimised. We fill an important gap, in that we reliably supply top-quality racing gearboxes for typically half the price of the OEM equivalent.
“We are constantly innovating, and we are currently introducing a dog-ring-type gearbox that meets the Superbike championship regulations yet provides faster and more-reliable shifting than conventional gearboxes.”
Now that Nova has installed its own vibratory-finishing bowls for super-finishing — supplied by Bletchley-based PDJ Vibro Ltd (
www.pdjvibro.co.uk) — there are very few gears, shafts and selector parts that do not undergo this process. Previously, only around 30% of the certified motor-sport-steel components underwent the treatment, due to the high cost of sending them out for finishing. Raising the proportion of super-finished components to nearly 100% has resulted in a major improvement in the quality, appearance and reliability of Nova’s products.
“Super-finishing is becoming very popular in the motorcycle world,” says Mr Whittaker. “Oil quenching parts during heat treatment means that the various components take on a different colour, ranging from light brown to green-grey to yellowish. This means that the assembled gearbox tends to look non-uniform, which detracts from its appearance. After super-finishing, all the component parts have the same highly polished appearance — and the engraving shows up better.
“Moreover, there is no doubt that the gearboxes last longer, as the time between our supplying a gearbox and getting it back for refurbishment is now greater. This is because there is less wear on the gear teeth — plus less friction between the bearings and the hard-turned diameters on the input and output shafts. Anecdotal feedback from some of our customers suggests that they also experience a small increase in power when racing, although this is difficult to verify.
“A further benefit of polishing the moving parts in a gearbox is that the time needed for running-in is shorter. Few bike racers adhere to the recommended period anyway, and some ‘pin it’ on the track immediately, so having a gearbox that requires less running-in is a big advantage.”
Choice of super-finishing process
When Nova’s directors decided to bring super-finishing in-house, a Google search led immediately to PDJ Vibro’s Web site. Mr Whittaker and his colleagues were keen to avoid processes that use chemicals, such as the acidic isotropic method used by its previous super-finishing service provider. One drawback is the expense associated with disposing of the chemicals after use. Another is the tendency of the treatment to erode the metal surfaces and alter component tolerances, which at Nova can be as tight as ±5µm.
PDJ Vibro recommended the use of porcelain and paste in its vibratory bowls; surfaces are polished, but the amount of material removed is negligible. This has been proved by Nova.
In addition to super-finishing bare metal surfaces, the company polishes some components that have been Tuftride-hardened rather than induction-hardened; there is no discernible change to the 5µm-thick Tuftride layer after
the vibratory-bowl finishing.
Further evidence of the microscopically small amount of metal removed by the porcelain medium is provided by the very fine machining marks — such as a single-point turned finish on a shaft — that are still visible on the surface of the metal after super-finishing. Two EVP vibratory bowls were supplied by PDJ Vibro after completion of successful trials on sample steel gears and shafts at its Bletchley technical centre.
A batch of parts is processed for five hours in one of the two 100-litre-capacity bowls, which is filled with two sizes of ceramic medium to optimise finishing over the entire surface of the components. A recirculating water and detergent mixture prevents oxidation of the steel.
Afterwards, the components are transferred to the second bowl; this contains smaller porcelain stones, and the parts spend 16hr overnight being polished, again in a water and detergent mixture.
In conclusion, Mr Whittaker said: “PDJ Vibro handled our enquiry well. The bowls were well priced, and they are equipped with hour counters that are useful for calculating our charges; they also warn when the medium needs changing or a service is due. The porcelain medium in particular lasts thousands of hours, as it removes very little material, so running costs are low.
“The whole super-finishing process has proved a great success. It means that all of our manufacture is now in-house — except for heat treatment — allowing us to keep close control over quality and delivery. We can react very quickly to race situations and can produce components in two weeks, rather than the six months that most major manufacturers offer.”
Facts about Nova Racing
Nova (
www.novaracing.co.uk) has been making motorcycle gearboxes for over 25 years and has a range of classic and racing gear kits in regular production. The company has supplied prototype race gears to most of the major manufacturers; it is also the sole source of gear kits for some of the largest World Superbike manufacturers’ teams.
The company’s products have contributed to countless victories and multiple championships in British Superbike and British Supersport, and the firm continues to supply a large part of the grid.
Throughout the company’s history, its customers have won Isle of Man TT victories in all classes, and several prestigious records are held by teams and individuals using components designed by Nova for the rigours of road racing.
Nova gearboxes are used in countless national and club series world-wide, meeting the demands of the low-budget user for whom reliability is paramount. Some clutch parts are also supplied, and the company is now considering manufacturing engine components for Moto3. Shown to the right is a superfinished gear set for a Kawasaki ZX10 racing gearbox.