Cadwell Special In the winter of 1946/47 Brown and Vincent service foreman Norman Brewster approached PCV and proposed building a Series A Comet Special for short circuit racing until a new 500 cc model was ready. PCV agreed, but restricted them to using factory surplus parts. Brown used a Comet engine and frame with serial number TTC17 as the basis of the Special. TTC17 had earlier been ridden at
Donington Park by Captain Clark. Brown and Brewster rebuilt the bike and managed to get weight down to . The bike's name came from the location of its first outing, at
Cadwell Park. Vincent designer
Philip Edward Irving (PEI) was approached by the West Ham Speedway to build an engine similar to the TTC17 Cadwell unit for speedway use. PCV and PEI designed a modified engine that used a Rapide
cylinder head and barrel and a Series A engine case. All of the cooling fins were sawn off the barrel and cylinder head so that the engine would warm up quickly. The first engine had a crankcase of cast
Elektron metal. Eventually the Cadwell Special itself received a Speedway engine. The Cadwell Special was sold by the factory after the Grey Flash bikes became available.
Gunga Din PCV determined to create a racing model out of the Rapide. A rejected engine, F10AB/1A/71.1, was sent to the development department and completely rebuilt, then mounted in a frame. The bike was soon put to use as a factory racer, as well as a test-bed for performance improvements to be applied throughout the line. This bike was named
Gunga Din by motor journalist Charles Markham.
Nero Brown wanted to continue racing, and wanted to do it on a bike like Gunga Din. He located a Rapide in Mill Hill, North London that had been damaged in a crash and subsequent fire and bought it for £5. Brown and his brother Cliff rebuilt the wreck, and as they were no longer working for Vincent, were able to make any changes to the bike they wanted. Custom camshafts were made, and the compression ratio was raised to 13:1. Brown originally built the bike known as Nero to be a road-racing machine. The bike was raced in both solo and sidecar configurations. In 1954 more obvious changes were made, when the rear swing-arm was replaced by one fabricated out of Velocette swing-arm legs and dampers by the Browns thanks to diagrams done by George Buck, a technical adviser at Vincent. The Vincent girdraulic front end and wheel were replaced by a telescopic fork and 19" wheel from an
AJS Porcupine, courtesy of
Jock West, AJS' sales director. With these modifications complete the bike's wheelbase was the same as a Norton featherbed; . This caused the front wheel to lift under hard acceleration, so Brown lengthened the wheelbase by . The bike underwent steady revision. By 1959 the compression ratio was up to 25:1, and power was approximately at 6,800 rpm. The forks were AMC
Teledraulic telescopics. The bike retained the box-section backbone chassis of the donor Rapide, and the 998 cc 47° Vee-twin cylinder layout. One year later the bike received 1 7/32" GP carburettors. The rear end was lowered with shorter springs, and the wheelbase was stretched an additional 2½". To handle the extra power a modified Norton clutch and seven friction plates were installed. Brown heard about a new type of tyre called a
slick being used in America. He contacted Avon Tyres and had them duplicate the American product for Nero; the first use of such tyres in Great Britain. Brown later extended the rear swing-arm another , and extended the front rebound springs. Brown also had a streamlined fairing made for Nero; the first such use of aerodynamics on a bike in Britain. The first one built was of aluminium, and three more were made in fibreglass. They were used on both his custom bikes as well as the factory specials he also raced.
Nero replicas Brown built three replicas of Nero for private owners. One was built for Frenchman Marc Bellon. Bellon contacted Brown by telegram in September 1958 about modifying his personal Rapide, which he then delivered to Brown's workshop. The bike received an
AJS 7R telescopic fork and conical brake in front, and a Velocette-based swing arm with Woodhead Munroe shocks in the rear. Front and rear wheels were 19" with aluminium rims. The engine remained stock. Bellon put on his street Nero before being called up for military duty. On his return he found the bike in an unrideable condition, which is how it remained for 20 years. In the mid-1980s he began a complete rebuild that included Mahle pistons, MkII cams and Alton generator. The Vincent backbone was replaced by a custom large-diameter tube and the steering head with a unit of solid billet. The restoration was completed in 1998. One of the other Nero replicas was sold to a Scottish physician, who wanted to use it both on the street and in sprints. The other replica was sold to a shop-keeper in Eastbourne who kept it in regular road trim. Brown charged £450 for the conversions. Brown only built three, as most of his efforts then were going into building Super Nero.
Super Nero Brown's next bike was built with the goal of taking the World motorcycle land speed record. Construction started in earnest in June 1962 and the bike was first road tested in August. The team included Brown, his wife Ada, fellow sprinter Pat Barrett, and Brown's brother Cliff, who had worked on Reg Dearden's World record challenger ten years earlier. The bike was called
Super Nero, and had a supercharged engine. To provide the
forced induction, Brown obtained two 1500 cc
Shorrock superchargers. The engine was a Vincent 998 cc V-twin, built to Nero specs with Picador-type ground flywheels, high-lift rocker arms and Stellite cam followers. Compression was reduced to 8:1. The first incarnation of Super Nero used the modified Model-C Vincent frame from the original Nero, whose engine was then transferred into a new factory Model C frame. Nero's long swing-arm suspension was retained. Super Nero started racing in August. Power was estimated to be between . In early races it was determined that boost was too low, so
sprocket ratios were changed on the blower drive to increase it. Problems encountered included misfiring magnetos and breaking primary chains. The British Drag Association invited the American Drag Association to an exhibition series in England in 1964. American drag racers would complete with their British counterparts at six airfield tracks. Before the Americans arrived Brown decided to revise Super Nero in 1963. A new, lower frame was built from 5/8"
Reynolds 531 steel tube. The front forks for the new chassis came from a 70 cc
Honda Super Cub, and were shortened further for use on the new Super Nero. The front wheel was 17" in height. The head-lug was modified to accept the Honda ball-races. Rake was 30°. The gearbox also served as the oil tank for the engine. In 1965 Brown's brother Cliff built an experimental engine by boring out the mouth of the crankcase and having custom liners made for the barrel mouths so that the engine could be converted from 1000 cc to 1148 cc by inserting or removing the liners and installing the appropriate barrels and pistons. Brown built a special twin-coil ignition system for the bike as well. At this time they also discovered that the cause of their chronic misfiring was due to the batteries' plates being vibrated to destruction during the high-speed runs. The customised engine was run in Nero once at Swinderby, during which a
connecting rod broke and damaged the engine, after which the engine reverted to a standard crankcase. Both Nero and Super Nero are part of the collection in the National Motorcycle Museum in Solihull, West Midlands UK.
Super Nero Mark II Prior to the start of the 1966 racing season another bike was built that is known as Super Nero Mark 2 (or Mark II). The tubular frame was the same as that built for Super Nero. The engine was an enlarged V-twin that displaced 1148 cc, and was supercharged as well. Some references use the name
Extra Nero, which is believed to refer to this bike. ==References==