Triumph TR6C Trophy


Make Model

Triumph TR6C / SC / SR / SS Trophy


1961 -


Four stroke, parallel twin cylinder, OHV


649 cc / 39.6 cu in
Bore x Stroke 71 X 82 mm
Compression Ratio 8.5:1
Valve Clearance (cold) Inlet: 0.05mm / 0.002"
Exhaust: 0.10mm / 0.004"
Valve Timing Inlet Valve Opens: 34 degrees BTDC
Inlet Valve Closes: 55 degrees BTDC
Exhaust Valve Opens: 48 degrees BTDC
Exhaust Valve Closes: 27 degrees BTDC


1 x 30 mm Amal Monobloc carburetor


Lucas magneto
Spark Plug Gap 0.50mm / 0.020"
Timing (fully advanced) Crankshaft position 38 degrees BTDC
Piston position 11mm / 7/16" BTDC
Clutch Multi-plate, wet


Wet, multi-plate


4 Speed

Final Drive

Chain, 101 links
Gear Ratios 4th 4.88 / 3rd 5.81 / 2nd 8.25 / 1st 11.92:1

Front Suspension

Telescopic Forks

Rear Suspension


Front Brakes


Rear Brakes


Front Tyre

3.25 - 19

Rear Tyre

4.00 - 18
Dimensions Length 2190 mm / 86.25 in
Width    720 mm / 28.5 in
Wheelbase 1403 mm / 55.2 in
Seat Height 775 mm / 30.5 in

Dry Weight

173 kg / 380 lbs

Fuel Capacity 

18 Litres / 4.8 US gal / 4.0 Imp gal

Gone was the previous "A" & "B" designations introduced in 1960. The new nomenclature was TR6R for 'Roadster' with low pipes & TR6C for 'Competition', the enduro version with high pipes.

All went by the model name "Triumph Trophy". 1961 Triumph TR6 engine & frame numbers run from D8432 to D15756, built from Sept. 20, 1960 to Aug. 23, 1961. For 1961 the Triumph TR6 was not listed for sale in the UK.

In the interest of quieter operation, starting with Engine #D8858 a new alloy 'Delta' cylinder head was fitted with cast-in pillars between some of the cooling fins, to combat high frequency vibration causing a 'ringing' sound. Starting with Engine #D14438 the one-piece forged steel crankshaft now featured straight-sided webs & the central flywheel was increased in width from 2-1/4" to 2-11/32".

The balance factor now changed from 50% to 71%. Finally, the engine sprocket reduced to 21 teeth, lowering the overall gearing of the bike. In the gearbox, the sintered bronze layshaft bushings (bushes) were replaced with Torrington M11121 needle roller bearings.

Within months of its launch in 1960, the new Duplex Frames were cracking around the steering head. The factory quickly addressed it and 1960-model bikes were retrofitted by dealers with an additional bracing tube under the backbone, all under warranty.

Now, the 1961 Triumph TR6 and all other Triumph motorcycles sharing the duplex frame, got the additional bracing tube installed at the factory. Interestingly, most of the frame cracking problems were in the US & were later attributed to the brutal punishment the bikes were forced to endure in off-road racing.

Source classic-british-motorcycles.com