Triumph TR6C Trophy 
| Make Model | Triumph TR6C Trophy | | Year | 1961 | | Engine | Air cooled, four stroke, parallel twin cylinder, OHV | | Capacity | 649 | | 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 | 30mm Amal Monobloc | | 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 | | Max Power | | | Max Torque | | | Transmission / Drive | 4 Speed / chain | | Gear Ratios | 4th - Top 4.88 / 3rd - Third 5.81 / 2nd -Second 8.25 / 1st - Bottom 11.92 / RPM @ 10MHP in Top Gear638 RPM | | 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 86.25 in / 219cm Width 28.5 in / 72cm | | Wheelbase | 140.3cm / 55.2 in | | Seat Height | 77.5cm / 30.5 in | | Dry Weight | 380 lb / 173 kg | | Fuel Capacity | 18 Litres | 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 & 1960-model bikes were retrofitted by dealers with an additional bracing tube under the backbone, all under warranty. Now, the 1961 Triumph TR6 & 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 |