1956 Triumph Blackbird
ABOVE: The 1956 Triumph Blackbird was essentially a 6T Thunderbird painted black. This earned it the name “Blackbird”.
STUCK WITH THE IRON HEAD
The 1956 Thunderbird retained its old cast iron head and all its overheating problems, while the new alloy “Delta head” debuted on the Triumph Tiger T110 and the new for 1956 Triumph TR6. This not only solved the cooling problems but also eliminated the external oil drain pipes, now allowing the oil to drain back to the crankcase via the pushrod tubes. A thermal insulating block was installed between the head and the carburetor. Compression ratio was raised to 8.5:1 for the Tiger T110.
The 6T Thunderbird did get some performance upgrades, however. Shell-type big-end bearings replaced the previous white metal type. This called for larger and thus heavier connecting rods which required an rejiggering of the crankshaft balance factors.
Inside the gearbox, old phosphor bronze layshaft bushings were replaced with sintered bronze. The composition of he rubber clutch shock absorbers was changed. Inside the clutch, the driven plates were now solid instead of being drilled & the drive plates were now had bonded Neolangite friction surfaces.
Inside the front forks a new hydraulic bump stop prevented bottoming out during hard braking. The rear shocks were fitted with 100-pound springs with revised bleed and bump stops. In the headstock, the top ball race was changed to match the lower race.
A new sidecar lug was fitted to the seat post & the fuel tank was now rubber mounted & featured the now-famous 4-bar parcel grid. A new center stand provided greater ground clearance. The wiring harness was now sheathed in PVC.
BELOW: The 1956 Triumph Blackbird was inspired by the bike Marlon Brando rode in the 1953 movie “The Wild One”.
1956 Triumph Blackbird SPECIFICATIONS
Bore & Stroke
Final drive sprockets
|Air-cooled OHV vertical twin
649cc / 40.0 ci
71mm X 82mm / 2.79″ X 3.23″
8.5:1 (US & export); 7.0:1 (UK)
34 bhp @ 6500 rpm
1/2″ X .335″ X 5/16″ chain, 70 links
24T X 43T
4-speed, right foot shift