Triumph Trophy TR6C

Make Model	Triumph TR6C / SC / SR / SS Trophy
Year	1961 -
Engine	Four stroke, parallel twin cylinder, OHV
Capacity	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
Induction	1 x 30 mm Amal Monobloc carburetor
Ignition	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
Clutch	Wet, multi-plate
Transmission	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	Swingarm
Front Brakes	Drum
Rear Brakes	Drum
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

1961 TRIUMPH TR6 BY THE NUMBERS
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.

ENGINE MODS
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.

DUPLEX FRAME PROBLEMS ADDRESSED
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.

Triumph TR6C Trophy