1964 Royal Enfield Continental GT: “Britain’s fastest 250”

Bike Profile

1964 Royal Enfield Continental GT 250

Story: Peter Laverty • Photos: Jim Scaysbrook

The Thruxton 500, or Nine Hour Race, was an annual bash for Production motorcycles, or rather, what constituted Production motorcycles under the loose rules of the ‘fifties and early ‘sixties in England. All manner of stuff took to the track; some with plans of outright victory, others just hoping to finish and perhaps pick up a trophy. An entry in the latter class for the 1960 ‘500’ would have been the Royal Enfield Crusader, a mild mannered overhead valve 250cc single, ridden by R. Prowting and M. Munday. Up against some quick two-strokes and a selection of other quarter-litre machinery, the pair not only finished the gruelling event on the rough ex-WW2 airfield circuit near Andover in the south of England, but won their class. Hmmm, thought Royal Enfield, there could be a market here. 

There certainly was a market – the booming café racer society, with their silk scarves and leather jackets, were not all hell bent on thundering great British twins. Many, driven by needs of economy, just wanted something sporty, economical to run, and fun to ride. At the time, 250cc motorcycles were learner-legal prior to passing the official riding test. It was far from uncommon for young, hard-up pseudo racers to dress up their machines in whatever way they could afford; home made clip-on handlebars, racing style seats, air scoops for brakes and rudimentary rear set footrests. 

Extreme swept back exhaust and linkage to the rear-set gear lever highlight right side engine view.

Royal Enfield had the basis for such a machine in the Continental, itself derived from the Crusader which had first appeared in 1956. The existing 250 engine was unorthodox, in British tradition, in having its pushrods running up the left side of the engine, with the camshaft contained in the primary drive casing. The Lucas alternator sat on the right in a sealed compartment, so it did not share the engine lubricant, as was the usual practice. The crankshaft was in one-piece cast iron, with a light alloy connecting rod. Bore and stroke were nicely over-square at 70 x 64.5mm. One criticism from the outset was the imprecise nature of the four-speed gear box which was renowned for containing as many neutrals as gears. 

Pushrod tunnels can be seen on left side, along with rev counter drive and substantial crankcase breather.

 A Sports version of the Crusader was launched in 1959, with the original cast iron head replaced by an alloy casting with a bigger inlet valve, compression up from 7.3:1 to 8.5:1, a larger Amal Monobloc carburettor and lumpier cams. Fitted with clip-on handlebars and a perspex screen, the Crusader Sports was capable of almost 80 mph if you kept your elbows in. Importantly for the younger market, fuel consumption was listed as 92 mpg. 

Three years later came the Super 5, featuring a five speed gearbox – the first production British motorcycle to do so. A further increase in compression and carburettor size allowed road testers to squeeze 83 mph out of it, with improved acceleration to boot. Telescopic front forks gave way to leading link jobs. The Continental was born in 1963, with what quickly became known as the ‘jelly mould’ petrol tank, an air scoop for the front brake and sporty touches like exposed rear springs, ball end levers and a fly screen. 

Large capacity fibreglass fuel tank was the model’s signature.
Smiths instruments nestle in the classy shroud over the top fork crown.

Here then lay concept for the Royal Enfield Continental GT. The company’s latter-day boss, Leo Davenport, was a former leading racer and winner of the 1932 Lightweight TT on a New Imperial, who came up with the idea of producing a learner-legal, ready-customised machine that would appeal to the young tearaways. The actual design of the Continental GT was allocated to Reg Thomas in the Enfield drawing office, although Royal Enfield reportedly allowed the factory’s apprentices to have their say in what would excite them in the design of a café racer.

Beginning with a standard Crusader Sports, Thomas dispensed with the standard tank, substituting a very racy looking red fibreglass item with a quick release cap, secured to the frame by a rubber strap, a sporty dual seat with the mandatory racing hump at the rear, rear-set footrests with associated gear lever and brake pedal, swept back exhaust pipe and other small items designed to quicken the pulse of the young neighbourhood street racer. The clip-on handlebars featured racing style ball-end levers, and a small Perspex screen sat above the twin instruments which were contained in an alloy casting that sat above the top fork yoke, inviting the rider to adopt a TT pose. A rev-counter gearbox was fitted to the primary chaincase where it picked up drive from the camshaft. The imposing front wheel included a pair of enormous ‘cooling fins’, which in reality did nothing of the sort. The fins were not attached to the drum, but simply clipped to the spokes. Oh well, if it looks good…

Rubber moulding joins the crankcase to rear chain guard.

The mods also extended to the engine. The inlet port was opened up to accept a 1 1/8” Amal Monobloc fitted with a long fluted bell mouth in place of an air filter. Compression went up to 9.5:1 and special attention was paid to crankcase breathing. In pukka racing style, a large diameter plastic pipe exited the rear of the crankcase and ran all the way to the rear mudguard, where it discharged its vapours (and perhaps the odd trace of lubricant) into the atmosphere. Although this modification may seem insignificant, it was long overdue, and greatly helped in reducing crankcase pressure and the resultant oil leaks. Noting the gearbox’s well-earned reputation for vagueness, the Continental GT received special attention, and an extra cog. The fifth gear produced an overdrive ratio that propelled the bike’s top speed to something approaching 85 mph in very favourable conditions, although fuel consumption suffered, falling to 76 mpg. In reality, 7,500 rpm was the limit of the revs (equating to around 81 mph), after which power dropped off noticeably.

More for visual effect than purpose, large “cooling disks” surround the front hub.

There was a range of factory options available, including a fairing, air filter, a side stand, alloy rims, and even leading link forks. Sports-minded dealers – notably the UK Enfield specialists Gander and Gray – quickly chimed in with even more bling.

Many GTs were dressed up with fairings, such as this one on display at Classic Style, Seaforth, Victoria.

The vivid red Continental GT made its public bow in November 1964 in a blaze of publicity that was most unlike Royal Enfield’s normally stoic manner. The company planned to have one of the new GTs (the engine fitted with titanium push rods) make the trip from John O’Groats in Scotland’s extreme north, to Land’s End in the far south in 24 hours, with selected journalists riding different stages. As extra spice, former World Champion Geoff Duke (at the time running Royal Enfield’s race team) was on hand at Oulton Park circuit in Cheshire, where he climbed aboard and completed five quick laps. Soon after the GT arrived at Silverstone in the Midlands where John ‘Moon Eyes’ Cooper climbed aboard and completed eight laps of the near-frozen track, the quickest at a very impressive 73 mph. Cooper averaged 70.29 mph for the entire session. Including the race circuit intervals, the whole trip took just 22 hours and 20 minutes. 

John Cooper screams around Silverstone during the pre-launch publicity run.

It was a brave move by Royal Enfield, which was fighting on several fronts to ward off creditors and developers who were enviously eyeing the company’s site at Redditch, Worcestershire. RE correctly reasoned the GT would need all the razzamatazz it could muster, as the projected selling price (in UK in 1965) of £270 was only £56 less than a Triumph Bonneville, and eleven quid more than a Honda CB72, at a time when an apprentice wage was around £3 per week. Perhaps an even more serious competitor was the new Suzuki T20 – 10 mph faster and only 2 quid dearer.

Initially, the press raved around the GT, especially the handling. It was certainly quick, by British 250 standards, and undeniably a good looker. Importantly for the target audience, fuel consumption was listed at an astounding 115 mpg, not bad for a high compression sporty job, but a figure not remotely approached by any of the road tests of the day. As a sales exercise though, the GT underperformed – its price a major consideration, but the stiff competition now coming from Japan the deciding factor. Production lasted until early 1967, and in the final year, a US model with high-rise handlebars was produced in very limited quantities. 

The GT was not without its problems, however; many stemming from the gearbox which would find ratios disappearing. One fault was in the selector mechanism for the five-speed box, and one cure was to simply fit the old four-speed cluster. In fact, towards the end of the 250 GT’s production run, Enfield had despaired of ever curing the inherent problems, and gave away a four-speed cluster with every new bike sold. Those inherent problems with the five speeder lay partly in the fact that in order to accommodate the cogs in the existing crankcases, gears had to be reduced in width – and reduced in strength. Also, the four speeder had two sets of dogs on the second and third layshaft gears, but the five speeder had just one for second, third and fourth gears. The gearbox itself was hardly oil tight, so unless the level was checked regularly, further problems arose. 

The projected selling price (in UK in 1965) of £270 was only £56 less than a Triumph Bonneville, and eleven quid more than a Honda CB72, at a time when an apprentice wage was around £3 per week.

Royal Enfield itself was fighting a losing battle, and after the closure and sale of the Redditch site, production of the only remaining model, the Interceptor, was transferred to Westwood. Eventually, a complicated arrangement transferred the production of the Interceptor to Norton Villiers, while Veloce Ltd purchased the complete spares and service department.

However the prescience that resulted in the Continental GT of 1964 was not lost entirely. As such an enduring classic design, and with the renaissance in the café race culture, the present, Indian-owned Royal Enfield marque revived the GT concept in the form of the 535cc Continental GT, released in 2014 and now a very popular part of the range. 

Thanks to Classic Style, Seaford, Victoria (www.classicstyle.com.au) (03) 9773 5500 for allowing us to photograph the featured motorcycle.

1964 Royal Enfield Continental GT: Specifications

Engine: Single cylinder four stroke, cast iron barrel, alloy head
Bore x stroke: 70mm x 64.5mm 248cc
Compression ratio: 9.5:1
Carburettor: Amal Monobloc 1 1/8”
Lubrication: Dry sump, oil reservoir integral with crankcase
Power: 20bhp at 7,500 rpm
Electrics: Lucas AC lighting-ignition with RM18 60 watt alternator. 6 volt coil ignition. 
Transmission: Five speed in-unit gearbox, chain primary and final drive.
Frame: Single tube all-welded steel.
Wheels: WM2-17 steel rims. Tyres: 3.00 x 17 front  3.25 x 18 rear.
Fuel capacity: 3.4 gallons (15.5 litres)
Weight with one gallon of fuel: 300 lb ( 136kg)

This article first appeared in Old Bike Australasia Issue 58.