Hot Rod: BSA Spitfire Mark III

BSA weathered the war well, and by the 1950s it had the largest range of any motorcycle manufacturer in the world. Most of the bikes BSA sold were the smaller, single-cylinder commuter cycles heavily in demand by British workers. And while the company had a firm policy against factory road race involvement, BSA built single-cylinder Gold Stars for clubman racers in England and flat track competition in the United States.

BSA’s better twin

By this time, BSA’s parallel twin had morphed into two versions, the 497cc A7 and the 646cc A10. In order to raise money to pay its war debt, the British government pushed English companies to export. As a result, a lot of BSA twins were sent to the United States, where the market for sport motorcycles was booming. Indian motorcycle distributor Hap Alzina was importing BSAs to the West Coast while Rich Child, the former head of Harley-Davidson’s Japanese subsidiary, was in charge of distribution east of the Mississippi. The reliability and economy that drew British consumers did not draw U.S. riders, who were more interested in speed. American motorcyclists generally had little use for BSA’s lightweights, but were enthusiastic about BSA twins.

An obvious way to prove performance is on the race track. BSA didn’t like to sanction racing, but the company had little choice if it wanted to sell bikes in the United States. American racers found that BSA twins responded well to tuning, and with the right setup were competitive in flat track and offroad events. In 1954, BSA lent assistance to a team led by AMA National Champion Bobby Hill for that year’s Daytona beach race, and the BSA Wrecking Crew, as it became known, swept the first five places. Other National winners on BSA singles and twins included Jody Nicholas, George Everett and Dick Mann.

One of the most consistent BSA flat track stars was Al Gunter. He moved to BSA in the early Fifties and racked up seven career wins in national racing events. His home track was Ascot Park in Southern California, where he won regularly. Other BSA riding masters at Ascot were Sammy Tanner, Blackie Bruce, Jack O’Brien and Neil Keen. Together, they were known as the Ascot Wrecking Crew.

BSA continued to develop its parallel twin, and in January 1962 introduced a major revamp of both the A7 and A10 twins. The new engines were based on a common platform, with the major difference between them being the 75mm bore of the A65, which with the 74mm stroke common to both engines gave 654cc cubic capacity. The smaller A50’s bore of 65.5mm gave 499cc.

The A65 engine used vertically split aluminum alloy crankcases with a one-piece crankshaft resting on ball bearings on the drive side and a plain bushing on the timing side. The cylinder was still cast iron, while the head was aluminum alloy. Valves were operated by pushrods, and lubrication was dry sump.

The 4-speed transmission was in unit instead of a separate box bolted to the engine as on the A10, and an alternator handled the 6-volt electrics. Two sets of points were mounted on a single plate with an automatic advance mechanism.

The frame was similar in design to the one used on the last A10s, a dual downtube cradle with a single backbone tube under the seat. Telescopic forks in the front and Girling shocks in the rear absorbed the bumps, and the single-leading-shoe brakes were 8 inches diameter in front and 7 inches in the rear.

Going faster

In 1964 BSA started hot rodding the A65. The Rocket A65R had the compression upped to 9.0:1 from the standard 7.5:1, with a hotter cam and siamesed exhaust pipes. British riders still wanted easy maintenance and fuel economy, but American riders wanted higher bars, smaller tanks and more horsepower, so the American importers convinced BSA to build four special U.S.-only models.

The result was the 499cc offroad competition Cyclone with no lights and open pipes, and the 654cc Thunderbolt with high bars, a small tank and the hot engine. A twin-carb version of the Thunderbolt was named the Lightning.

The last of the four U.S.-only models was the 654cc BSA Spitfire Hornet. Like the Cyclone, it was produced in response to American demand for a hot offroad/desert racer. Equipped with the twin-carb head fed by a pair of 1-1/8-inch Amal Monobloc carburetors and available with either 9:1 or 10.5:1 compression, it had a 2-gallon fiberglass gas tank, a high-performance cam and straight-through pipes.

In line with BSA’s East/West Coast distributorships were separate East Coast and West Coast models. The East Coast version had high pipes and the West Coast model had low pipes. If riders wanted to hit the street, BSA’s ET (energy transfer) ignition system could be easily adapted to add lights.

By this time, BSA was experiencing cracks in the corporate wall. Better wages for English workers meant many of BSA’s get-to-work customers were buying inexpensive automobiles coming on the market, and Japanese motorcycles were being imported to England and America in record numbers.

Making matters worse, the British manufacturers weren’t reinvesting their profits into developing their products. In the 1960s, BSA was building motorcycles on machine tooling from before World War II. The Japanese manufacturers, however, were making major investments in tooling and design, enabling them to offer oil-tight cases, overhead cams and electric starting at prices competitive to the much more primitive English machinery. Certainly the Brit bikes handled better, but that was a priority for a minority.

BSA management, who had continued to believe that its customers were forever loyal, was discovering that the get-to-work rider who didn’t buy a car was likely to buy a Honda over a BSA.

New bikes

The company tried to cope by fielding state of the art advertising campaigns and building stylish motorcycles targeted to the sport rider. For 1965, BSA dropped the single carburetor A65R for the American market. There were now 11 versions of the twin, but the 499cc versions had to compete against the new Honda CB450, which had double overhead camshafts, constant velocity carburetors, an electric start and twin-leading-shoe front brake.

For 1966 there were only six versions of the twin, two 499cc models and four 654cc. To counter problems with the drive-side ball main bearing, it was changed to a lipped roller race. This turned out to be a bad move, as at high speeds the crankshaft could pull to one side and occasionally cut off the oil supply, resulting in a rod through the cases. Although BSA never acknowledged the problem, ingenious privateer mechanics developed a more reliable bearing.

The intake valves were enlarged, the transmission was improved, a timing notch was added to the flywheel and a balance pipe was added to twin carb models. The frame was revised, and two-way damping was added to the forks. A 12-volt system replaced the now outmoded 6-volt lights.

The BSA Spitfire was introduced, replacing the limited production Lightning Clubman. Amal GP 1-5/32-inch carburetors replaced Monoblocs and the 190mm front brake from the defunct Gold Star was standard. The Hornet (with the Spitfire half of the name dropped) continued in production as a desert racer. Actor Steve McQueen, a dedicated offroad competitor, tested the Hornet in 1966 and wrote up the test himself for Popular Science. He praised the BSA’s powerful engine and the excellent air cleaner, but downgraded the machine for excess weight.

“The Hornet also had a tendency to want to go its own way. I always had to stay on top of it. But it sure had a good-functioning powertrain,” McQueen said. “I also think the front forks should be raked on a more forward angle. With this adjustment, the BSA Spitfire would have a more stable ride in the rough and would be generally a smoother performer,” he continued.

Cycle World tested a Mark II Spitfire on the dragstrip and notched quarter-mile results of 14.9 seconds, with a terminal velocity of 89mph. Unfortunately, the once-excellent BSA quality control was becoming spotty, and a run of defective ignition points cams resulted in overheating and bad performance.

The problem was corrected the next year with the Spitfire Mark III. New for 1967 was a new rocker box cover with fins and an inspection hole (with cover) for checking ignition timing with a strobe. Compression was reduced a little to 10:1 from 10.5:1, and the GP Amals were swapped for easier to tune (and cheaper) 932 Amal Concentrics. The dual seat grew a hump in the rear, and the tires were mounted on aluminum Borrani rims.

The Spitfire was continued for another year (as the Mark IV) before it was dropped to make room for the Rocket 3 triple. BSA managed to keep going until 1972, when mismanagement, an aging product line and competition from Japanese motorcycle manufacturers drove the company into bankruptcy.

Don’s BSA Spitfire

Don Johnson is a little too young to remember the glory days of BSA flat track racing, but he likes BSA sporting motorcycles. “There’s a visceral quality to Brit bikes as opposed to the industrial quality of Japanese motorcycles,” he says.

Don is a collector who rides his bikes. When he happened across this Spitfire, he found it interesting and bought it. It was all there and only “slightly restored,” Don says. “I ripped it apart, examined everything and put it back together. It was all original and within spec.”

All sorts of things can go wrong during the restoration of a 40-year-old motorcycle, but Don lucked out. Pretty majorly, actually, as the issues that arose were limited to three items: sticking carburetor slides, a crumbling wiring harness and a leaky fiberglass gas tank. The popularity of old British motorcycles has given a boost to cottage industries that manufacture most parts, often with better quality control than the originals, and you can still buy new Amal carburetors and parts for most Amal models produced since World War II.

A new wiring harness was easy to find, and Don says that most of the criticism aimed at Lucas “Prince of Darkness” electrical parts should actually be directed at the wiring harness. “Some stuff was not up to the task, but most Lucas components are reliable if you keep them clean and adjusted,” Don says. “Most parts got no attention until they quit. But Lucas does have one advantage — you can fix most things at the side of the road.”

The part that was hardest to repair was the gas tank. Old fiberglass tanks tend to weep and seep. As purchased, the Spitfire had a metal BSA Lightning gas tank bolted on, with the correct fiberglass tank in a box. Don discovered a new-old-stock tank in the shop of an acquaintance, and decided to buy it and use it instead of the compromised original.

Modern gas is hard on old fiberglass tanks, and a partial remedy is to carefully coat the inside with clear epoxy sealer from outfits like Caswell. But as experienced users will tell you, coating the inside of a tank is an art. Don pours in the compound and waits until it looks like it is starting to harden, then turns the tank so that the excess epoxy settles where he thinks the leak is. Since the filler neck is proud of the tank, getting excess epoxy out is very difficult, so Don just turns the tank so the last few spoonfuls settle at the bottom.

Don says that properly tuned and prepped, the Spitfire isn’t too hard to kickstart. “It was the hot rod of BSA’s line of twins after they discontinued the Rocket Gold Star,” Don says. “It’s as fast as a Triumph if it’s tuned right, and it stops a lot better than Triumphs of the era. Nowadays, I just like to putt along and enjoy the scenery. It handles very nicely for what I like to do. The lights are adequate, and the suspension is not bad. If you do it up right the Spitfire is reliable. It sure is eye-catching. It’s so red.” MC