· Competitor to the Honda CB750 Four Cylinder

· First 3 Cylinder production bike

· Extensive engine modifications by Big D Cycle

· Daytona winner in AHRMA Vintage Racing

The Triumph T-150 is a landmark British race motorcycle that was built to compete against the 4-cylinder Japanese motorcycles of the late 1960’s and early 1970’s. They differed from previous British race bikes in that they offered 3 cylinders for more performance at higher engine RPMs whereas prior motorcycle racers from the UK were either single or twin cylinder bikes.

The bike was developed jointly with BSA (Birmingham Small Arms) which marketed their version as the Rocket Three while Triumph called their 3-cylinder bike the Trident. They were the first production 3-cylinder motorcycles offered to the public. Minor differences in engine layout could be seen as the BSA version had a slight forward cant to the cylinder bank while the Triumph was vertically oriented. Not only could the triple achieve higher engine RPMs than a twin or single, but with a 120-degree crankshaft, the power delivery was much smoother and carried far less vibration.

The T-150 was in the works as early as 1965, but engineers and stylists at BSA (who owned Triumph) wanted to debut the motorcycle with a new look and visual design and delayed the bike’s release until 1968. Brought to market one week prior to the new Honda CB 750 4 cylinder, the bike was poorly outfitted in comparison and sales lagged. One place the Triumph/BSA 3 cylinder could shine was on the racetrack. While Honda captured the win at Daytona in 1969, BSA and Triumph rode to victory with Rocket 3 and Tridents in the 1970 race and placed well in competitions in the UK the same year.

One significant advantage was the BSA frame, which had two down tubes in front of the engine, where the Triumph had a single tube which carried over from their twin cylinder bikes. To make the Triumph more competitive, custom frame builders like Rob North of California, developed perimeter cradle frames that provided rigidity and strength to the Triumph racers. Perhaps the best know Trident racer was called “Slippery Sam”, a bike nicknamed as it leaked oil in its initial race, but followed up with numerous victories at the Isle of Man TT races.

The bike shown here is a highly modified 1974 version of the Trident, complete with a Rob North copy “cow boy” racing frame and many performance enhancements to the engine and running gear. The engine built by Big D Cycles in Dallas TX, features a lightened and polished crankshaft, high compression pistons, a single plate dry clutch, oversized valves and titanium springs, a five speed Quaife transmission and a belt driven primary drive. Frame enhancements include heliarc welded tubing, Marzocchi racing forks, Works Performance shock absorbers and oversize Akront alloy rims with Dunlop tires. While a stock Trident would make 58 horsepower, this racer put out 85 horsepower at 8200 rpm with a top speed of 162 mph on the high banking of Daytona.

The bike shown had a long racing career piloted by Rhode Island racer James Gubelmann up until 1992 at which time a serious accident at Road America in Wisconsin forced James’ retirement. Subsequently, James sponsored Richard Moore to race the bike in AHRMA (Vintage) races resulting in a win at the 1993 Daytona Speedway 750 GP Class, beating championship riders such as John Long and Gary Nixon.

In 2025, the bike was entered at the Audrain Concours, after which time Gubelmann generously donated it to the Audrain Collection.

Specifications:

Engine: Modified 3-cylinder 747cc twin cam pushrod OHV, Lightened and balanced crankshaft, oversized valves, high compression pistons and extensive cylinder head polishing, 5 speed gearbox, dry clutch, twin Amal GP carburetors, belt primary drive

Frame: Shortened wheelbase perimeter arcwelded chrome moly steel, repositioned engine angle, extended swingarm, Marzocchi front suspension, Dual Lockheed disk front brakes, air tunnel tested letterbox fairing to allow airflow to the oil cooler

Performance: 85 horsepower at 8200 rpm; 162 mph top speed

Weight: Stock bike 503 lbs; Race bike 422 lbs

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