Until the Honda 'Super-Cub' (or 'Step-Thru') became the immortal motorcycle of the ages (51 years and counting; untold millions produced), the Norton 16H had the distinction of the longest production run of any motorcycle in history, at 47 years. The model has its roots in the earliest days of Norton Motors (est'd 1898), when they began producing their own engines in 1907. 
Prior to this, James Lansdowne Norton (pictured here in 1910) had used French Peugeot or Belgian Clement engines, making a mere a handful of machines, seemingly only for himself and a few friends. Even after that epochal first-ever TT win in 1907 (using a Peugeot v-twin motor), Jas L Norton had not thought to take an exhibition space at the Motor Cycle Show - luckily the Peugeot company put the Rem Fowler TT machine in pride of place on their own stand, and much public interest was generated.
Unfortunately for Peugeot, the race win and subsequent attention gave Mr. Norton pause, and he quickly re-designed that v-twin engine with a few of his own improvements (like twin cams and roller mains), while adding a 3 1/2hp single-cylinder sidevalver to his modest range (with fully mechanical valves). The new single-cylinder model, progenitor of the 16H and clearly similar in layout and appearance, is shown above, in an advert from 1908. Note pedal-starting gear and long, high frame.
While many private owners came to love this single-cylinder machine, and had successes in all sorts of road trials, hillclimbs, and reliability trials, further success at the TT eluded Nortons since that first TT. (The photo below is from Brooklands, Easter 1909 - note early style high-saddle frame, 'tiller' handlebars, and pre-cursive 'Norton' logo on tank).
After being trounced in the 1911 TT by a 1-2-3 Indian victory (the Indians had chain drive, clutches, and a two-speed gearbox, while every English machine used a single-speed clutchless belt-drive), James Norton, a staunch and upright Christian, took out a full-page advert in The Motor Cycle:
"The American invasion, of distinctly American motorcycles, of distincly American design, built for distinctly American conditions, should prove a warning to the wide awake Britishers. Machines manufactured abroad of foreign material and designed for service under different conditions never CAN be as reliable and efficient as a British built, made in England, of British material, by British workman, designed for British service."
One famous incident involves Jack Emerson (above), who, after purchasing his TT model in September 1912, rode it 165 miles (from his home in Hull) to Brooklands, then entered the 150-miles Brooklands Senior TT. He led a field of experienced racers, and set 3 World's Records (including 73.5mph for the flying mile, the two hours, and the 150 miles - at an average of 64mph). His engine was stripped for inspection afterwards, and was found to be totally standard with the exception of stronger valve springs. The belt drive ratio was set to keep the engine running just over 3000rpm of the race (using a cast iron piston). Emerson rode the 165 miles home the following day. Interestingly, in Octoboer 1912, Emerson's Norton proved faster than the four-valve ohv singles of Oliver Godfrey (Indian) and George Stanley (Singer), at 67.72mph
. Note in the photo - still the high-saddle frame and old-script 'Norton' logo.
Which is ironic, given that every British manufacturer had been given a sound drubbing!
Out of this humiliation, just six months later (in late 1911), the TT 490cc Record Type was introduced (see above) with a new, lower frame, the infamous 79x100mm engine dimensions, and shorter wheelbase - Norton's first purpose-built racing machine. Although Norton still didn't apply the advantage of gears and a clutch, this model became a great success in competition, winning regularly at many local and national events, barring the TT for which it was named!
Out of this humiliation, just six months later (in late 1911), the TT 490cc Record Type was introduced (see above) with a new, lower frame, the infamous 79x100mm engine dimensions, and shorter wheelbase - Norton's first purpose-built racing machine. Although Norton still didn't apply the advantage of gears and a clutch, this model became a great success in competition, winning regularly at many local and national events, barring the TT for which it was named!
One famous incident involves Jack Emerson (above), who, after purchasing his TT model in September 1912, rode it 165 miles (from his home in Hull) to Brooklands, then entered the 150-miles Brooklands Senior TT. He led a field of experienced racers, and set 3 World's Records (including 73.5mph for the flying mile, the two hours, and the 150 miles - at an average of 64mph). His engine was stripped for inspection afterwards, and was found to be totally standard with the exception of stronger valve springs. The belt drive ratio was set to keep the engine running just over 3000rpm of the race (using a cast iron piston). Emerson rode the 165 miles home the following day. Interestingly, in Octoboer 1912, Emerson's Norton proved faster than the four-valve ohv singles of Oliver Godfrey (Indian) and George Stanley (Singer), at 67.72mph
. Note in the photo - still the high-saddle frame and old-script 'Norton' logo.Despite this sort of success, Norton's company was in dire financial straits, and the man himself in poor health (suffering from a congenital heart condition). By the end of 1912, his Norton Motors was bankrupt. (See photo of 1911 3 1/2hp model, with pedalling gear now gone. Also, in the photo below, Norton is standing with Freddie Barnes of Zenith in 1910).
His principal components supplier, R.T. 'Bob' Shelley, being a good friend (and largest creditor!) to Norton, purchased the company from the receiver, hiring 'Pa' Norton (his poor health had prematurely aged his appearance) to be joint Managing Director. Charles. A. Vandervell (Chairman of the Board of R.T. Shelley Ltd.) became Chairman of the new Norton Motors Ltd. Bill Mansell was hired to oversee production, and was responsible for Norton's future in racing; having seen the value of competition as advertisement, he made certain that Norton had a full complement of machines and riders (their first Team entry) for the 1914 TT (it being too late to mount a '13 effort).
Not that the 1914 Norton Team was successful, although two bikes did finish (in 46th and 51st place, ridden by O.G. and R.J.P. Brand - brothers seen in leather in this team photo, with Norton and D.R. O'Donovan). The third, 'dnf' entry was ridden by the brother-in-law of the Chairman of the Board, and while we all decry nepotism, this fellow happened to be Daniel R. O'Donovan, who had already established himself as one of the 'stars' in the Brooklands firmament, having been a Works rider for Singer, and a tuner of some renown.
'Wizard' O'Donovan, in concert with Bill Mansell, had by 1913 begun to modify the 'TT' model into the 'Brooklands Special' (BS) racer, with a guarantee that the engine had exceeded 65mph for one lap at the track. Note that the guarantee did not include the cycle parts! Each 'fast' engine was installed in a 'slave' chassis, managed by O'Donovan himself, now Norton's chief tuner.
That test chassis, having housed so many quick and famous engines, gained the name 'Old Miracle' (which set 112 Worlds Records in total - see photo, and note 'CAV' round magneto - Charles A Vandervell made magnetos!). When asked in later years how he managed to make so many engines pass the test, 'Wizard' confided that the trick was to ride the test machine near the top of the steep Brooklands banking, then drop quickly down the slope for the timed kilo! The BS weighed just over 200lbs (90.7kg).
The science of combustion chamber shape, inlet and exhaust porting, cam profiles, compression ratios, and carburation were all in their infancy, and pre-20's, the best 'tuned' Norton engines came from variations in the iron foundry process, rather than some intentional series of modifications to a standard motor. Some engines simply went better than others, and the quickest engines made their way to the racing team, or to selected rider/tuners at Brooklands. (Color pic above shows George Cohen's personal 'BS' model)
.The difference between an ordinary engine and one of these 'good' motors could bring a 15mph improvement on the track. An exemplary incident happened in 1914, when the factory made changes to its cylinder casting moulds - the new cylinders turned out much smoother than the old. But, O'Donovan couldn't get a single one of these new engines to pass 'the test', and much head-scratching ensued. Finally the penny dropped and the old moulds were rescued from the scrap heap - something about those rough castings improved combustion and gas swirl, although only Harry Ricardo was doing research into engine dynamics at this early date (two immediate results of his research were four-valve cylinder heads, and 'Riccy plates' inside sv combustion chambers to raise the compression ratio).
(Pic above, the French Show 'Brooklands Road Special' of 1914 - full mudguards, rack, and toolboxes - and no silencer!). O'Donovan continued to develop his machines at Brooklands, and on April 6, 1914 he managed to beat the 80mph barrier on a 500cc machine for the first time, gaining 81.05mph for the flying kilometer. This on a belt-drive sidevalver using a cast-iron piston, unknown fuel octane rating, cast-iron one piece cylinder barrel and head, with a chassis barely evolved from the bicycle. By the way, he also used the Binks 'Rat Trap' carb. See advert below, boasting a few records set by 'Wizard' during 1914.
In November 1914, Norton finally announced that an all-chain drive, clutch-and-gearbox model would be included for the 1915 range. The direct-drive models still included the Brooklands Special and Brooklands Road Special (BRS - with mudguards and toolboxes) and TT model, the BS now having a guarantee of a 70mph lap and 75mph over the flying kilo. The TT machine had no guarantee, but was claimed to be good for 65mph.
It took until 1919 for the Model 16 to appear (the H stood for 'Home Market' - there was also an export version, the 16C for 'Colonial'), although it used the same engine (79x100mm) built since 1911 (with improvements of course). The new model number heralded the arrival of all-chain drive, and the familiar configuration of flat-tank sidevalver we have come to love. Norton raced this model in the TT, coming closest to a win in 1920 (although they did fill 9 of the first 14 places), although Tommy de la Haye and his Sunbeam 'long stroke' racer proved faster.
On March 29, 1921, Rex Judd (above, on a bike and in the 'chair'), new to the Norton team at Brooklands (and weighing a very useful 125lbs/57kg), ran an amazing 92.44mph on O'Donovans 16H. This was the fastest the 16H would reach for in 1922, for the factory had introduced the Model 18 (500cc ohv, also 79x100mm), which was, right out of the box, 6mph faster than the older model, and instantly our humble hero was relegated to 'sporting' status. Still, the sidevalve model continued to be raced even until the mid-1930's, when the indefatigable A.L.Loweth rode his specially tuned 16H to 94 mph at Brooklands in 1934. It must have been sheer cussedness which inspired Loweth to seek out the last nth of speed from an obsolete design, but we're grateful he did.
During the later 1920's (pic above shows 1923 model) and through the 1930's, the 16H was produced in great numbers, as it still had a reasonable turn of speed, and was simply stone reliable. Overhead valve machines had their problems with lack of lubrication in the days when rocker arms and valves were exposed, but the 16H had proved its dependability, and most buyers who relied on their machines to get them to work valued the Norton's combination of decent power and unfailing dependability, plus Norton's legendary good road manners.
As the decade turned into the 1930's, the saddle tank frame with lower seat height was introduced to all models, which included thicker wall tubing and generally heavier spec on all metal items, which gave further smoothness to the ride and unbreakability to components, with a profound minus on performance; although top speed remained the same, it was taking longer to get with model change.
The 16H engine gained a detachable cylinder head (1931) and enclosed valves, but these gave little additional power. The greater weight (370lbs) of these 30's examples meant performance (65mph top whack) slipped further behind the new top-of-the-range ohc International model, which could be tuned with ease to reach 100mph usually by removing the silencer baffles).
During the Second world war, no less than 100,000 'WD' 16Hs (above - a late 1940 model) were produced, fully a fourth of the entire output of military motorcycles from Britain.
These carried quite a little extra weight over the production model, with a few parts made from cast iron, plus pannier bags etc, adding up to about 385lbs for a typical model - not exactly a lightweight. This photo seems to include good portion of those hundred thousand bikes!Postwar, the 16H was still produced in large numbers, for use especially for foreign military and large contract buyers
(such as the RAC, and Indian constabulary), usually as a workhorse sidecar hauler.
Individual buyers often used them for the same purpose; attached to a sidecar, for hauling the family, before cheap cars became affordable to the average worker.Over time, the cycle parts gained Roadholder forks, and eventually even a plunger frame, and the last models were actually quite fetching, albeit very slow by contemporary standards.
The advent of lower-cost cars and rising wages spelled the end of the age of family sidecars, and the 16H lost it's final utility, and was quietly dropped from the range in 1958.Most 16H models ended up being literally driven to death, off-road as 'field' bikes, or simply ridden by negligent owners until they were so worn out they were sold for scrap.
It became difficult in the 1960's and 70's to find a usable example of this model, especially the later versions.It's hard to imagine, looking at the WW2 16H, or the postwar dinosaur model, that in its youth, the old warhorse had been as fleet as a greyhound, and the terror of road and racetrack. By the end of production in 1954, it was simply heavy and slow (although reliable), all the glamour of its youth having long since faded away.
And yet...there has been a resurgence of interest in the model in the past 10 years; after many years of laying in the shadow of its ohv and ohc brothers, the 16H, especially those early, light, flat-tank models, have grown steadily in demand and consequent value. After dusting off the layers of history, it appears the old luster is back.
Sources of images and information; 'Flat Tank Norton' - George Cohen (the best!), 'Norton' - Mick Woollett, 'Norton' - Derek McGrath, 'The Unapproachable Norton' - Bob Holliday, 'Norton Singles' - Roy Bacon, 'Norton' - Don Morley
A good source of information on the military 'WD' 16H is www.wdnorton.nl