It’s a proven formula: outstanding track performances beget memorable production bikes like the BSA Super Rocket.
In 1951, a soft-spoken, self-effacing motorcycle racer named Gene Thiessen from Eugene, Oregon lined up a couple very special BSAs on the Bonneville Salt Flats. They were tuned versions of BSA’s new OHV parallel twins, first seen in road-going form the previous year: the 500cc A7 and 650cc A10. Though BSA officially disdained racing, the factory maintained a competition shop and made performance parts available to privateers. Newly appointed US west-coast distributor Hap Alzina was keen to promote his business, and arranged for the special 650cc bike to be supplied from the factory. The 500cc A7 was Thiessen’s own Daytona race bike.
With Thiessen as pilot, Alzina planned to challenge the AMA 500cc Class “C” (max 8:1 compression, gas fuel) and 650cc class “A” (any fuel, any compression) records. The rider removed the seat for the record attempt, spreading his weight over the rearset footpegs, handlebars, and rear fender. His clothing consisted of a pair of tights, cloth aviator helmet and basketball shoes. His two runs on the 500 set a new class C record at an average of 123.69 mph.
And so to the 650. To run class A, the iron engine was modified for alcohol fuel with 14.5:1 compression and a special twin port head fitted with two one-inch Amal TT carbs. Previous runs at Rosamond Dry Lakes had shown that with 15:1 compression on alcohol, the pistons would start hitting the cylinder head near the 6,200 rpm redline, so 14.5:1 pistons were used at Bonneville.
The first run was fast. By the tachometer and his gearing tables, Thiessen knew it was over 150 mph, and the timing confirmed that. But the price was a broken rocker oil feed. With only 30 minutes allowed between runs, a repair was hastily made, and with some nitromethane added to the fuel, Thiessen set off for the return trip. Again he knew he was running well over 150 mph, until, with a quarter mile to go, the engine seized. Thiessen grabbed the clutch and coasted the last 400 yards—yet still recorded a two-way average of 143.54 mph, a new Class A record.
Thiessen went on to race at Daytona in 1954 as part of the eight-member BSA team that swept the first five places in the Handlebar Derby with a mix of Gold Stars and A7 twins. In honour of these achievements, BSA released a sports version of its 34-hp 650cc A10 Flash called the Super Flash, with an alloy cylinder head and Amal TT9 racing carburetor. Although the engine made 42 hp, it was still installed in BSA’s dated “plunger” frame.
BSA re-packaged the A10 for 1955 with a new swingarm frame. In due course, a tuned version arrived using the Super Flash engine in the new swingarm frame, and renamed Road Rocket.
The 650 engine was revised in 1958 for better durability with a stronger bottom end featuring a one-piece crankshaft. Not surprisingly, there was also a tuned version, the BSA Super Rocket, with higher compression and Amal Monobloc carb for 43 hp. The Super Rocket was BSA’s flagship model until the new unit construction A65 Lightning Rocket was announced for 1963.
Presumably to use up stocks of frames and engines, however, BSA produced the ultimate version of the A10 in late 1962, fitting surplus Super Rocket engines (re-tuned to 46 hp) into Gold Star chassis and running gear. With an aggressive riding position (thanks to the Goldie-style clip-ons) optional RRT2 racing transmission, 190mm alloy front brake, siamesed exhaust, reverse megaphone muffler and easy100 mph-plus performance, the RGS was the definitive café racer of its day. It’s recorded that only around 1,200 of these desirable road-burners were produced—though enterprising customizers have ensured that more than that number have survived. So if you’re looking to buy one, caveat emptor!
Gil Yarrow’s 1960 BSA Super Rocket came from Billings, Montana as a basket case. “It needed a complete restoration,” he says. “Everything was in pieces, and $7,000 worth of parts were missing.” Yarrow rates trying to figure out exactly what was missing as the most difficult part of the restoration.
He started work on the BSASuper Rocket in 1999 and completed it in 2001, but finding the right parts wasn’t a problem; not even the correct carburetor drip tray—intended to keep gas dripping off the carburetor from dousing the magneto. And he’s pleased with the end result. “It’s a lovely bike to ride,” says Yarrow. “The handling is especially good.”
by Robert Smith Canadian Biker #312