1963 Triumph TR6
1963 TRIUMPH TR6 BY THE NUMBERS
The only model for 1963 was the Triumph TR6 S/S (Street Scrambler). Engine numbers ran from DU102 to DU5790 with build dates running from Sept. 29, 1962 to August 14, 1963.
UNIT CONSTRUCTION FINALLY HITS THE 650s
Unit Construction, all the rage in the late 1950s when most British Motorcycles were of a non-unit design, was sweeping the industry. Triumph was no exception. In 1957, they converted their 3TA 350 twins to unit construction, following in 1959 with the 500 twins. This was the same year as the launch of the Bonneville, and sales of the mighty 650 twins were shattering all expectations. So, they left well enough alone, waiting until the 1963 model year to convert the entire 650 line to Unit Construction. The 1963 Triumph TR6 was one of them to feature the new engine package, incorporating the engine, gearbox & primary case into one unit (hence the name “Unit Construction”). But it also got an entirely new frame, the best Triumph frame ever.
UNIT CONSTRUCTION ENGINE: OLD AND NEW
Of course, nearly every part of the new engine was redesigned, yet many of the old Pre-Unit components would fit, or nearly fit the new engine. In other words, it wasn’t a total clean-sheet design, it was an evolution of an older design, in this case one that dated back to the mid-1930s. Of course, the entire crankcase was completely new, but so was the top end which now got a ninth head bolt. The crank now got its oil supply from its timing end for greatly improved flow. Gearbox was familiar, but repackaged for the new cases. The primary drive was of course also new, with a 84-link 3/8″ duplex chain, a 58-tooth cast iron clutch basket & a 29-tooth engine sprocket. The cush drive in the clutch center was changed & the number of clutch springs reduced from 4 to 3.
A BRAND NEW FRAME
With the new 1963 Triumph TR6 came not just a new engine but a new frame as well. Gone was the old “Duplex Frame” with all its steering head weakness & lack of swing arm pivot support. And gone to was the tendency of pre-unit Triumphs to weave & wobble at high speeds. The new frame had a single front downtube (of 1-5/8″ diameter 12-gauge steel) which split into two frame tubes under the nose of the engine running under the engine toward the back. The rear subframe bolted on & the swingarm pivot, now a heavy cast lug, was secured at both ends to the rear engine mounting plates, & through them to the rear subframe & the engine itself. For the first time, the swing arm pivot was well supported & very rigid. It paid big dividends in handling & Triumph Motorcycles quickly became known for them exceptional handling.
A MIX OF OLD & NEW RUNNING GEAR
The of mags & dynos were relegated to history. In their place, a compact modern alternator was mounted to the primary (left) side of the crankshaft in the primary chaincase. It powered the 6-volt electrical system along with the contact breaker/coil ignition system. Two rubber-mounted Lucas MA6 coils under the tank provided spark. The Lucas 4CA contact breakers were now mounted on the timing cover at the end of the exhaust camshaft. New 7/8″ rubber-mounted handlebars, new 3- and 4-gallon fuel tanks with two rubber mounts in front & one in the rear, new seat, side cover & much more was changed, but many Pre-Unit components carried over, at least for the first few years. Slow evolution, Triumph tried not to change too much all at once. For instance, the front forks on the 1963 Triumph TR6 were identical to those on the 1962, but were changed for 1964.
1963 Triumph TR6 SPECIFICATIONS
Bore & Stroke
1963 Triumph TR6 S/S (Street Scrambler)
Air-cooled OHV vertical twin
649cc / 40.0 ci
71mm X 82mm / 2.79″ X 3.23″
1- Amal Monobloc, 1-1/8″
Battery & coil, Lucas
42 bhp @ 6500 rpm
3/8″ triplex chain X 84 links
Engine 29T X Clutch 58T
4-speed constant-mesh, right-foot shift
5/8″ X .400″ X 3/8″ chain X 106 links
Gearbox 19T X Rear 47T
Brazed lug, full-cradle, single downtube
Telescopic fork, hydraulic damping
Swing arm, 2 Girling dampers
8″ SLS drum, full-width
7″ SLS drum, one-side
3.25″ X 19″ Dunlop
4.00″ X 18″ Dunlop
2.5 Imp gal (US)/4 Imp gal (UK & export)
54.5″ / 140.3 cm
32.5″ / 77.5 cm
5.0″ / 12.7 cm
363 lbs / 165 kg