Tiger Cub T20 (& T20J) 1961/62
Styling-wise for the next two years it was very much a case of carry on as the 1960 model with the exception of a new rear light unit (Lucas L564 type), which did away with the need for a separate rear reflector.
Engine-wise though, a number of changes aimed at ensuring longevity came in the form of a new cast iron bodied oil pump (from engine No. 81890). Said to give a better flow rate when the engine and the oil was hot. Then from engine number 84269, a new crankcase came into service which replaced the timing side main bearing plain bush with a ball journal bearing.
The original bush material had changed a number of times over the years in the quest for maintaining good oil pressure to the big end bearing, but none had really fully answered the problem of the bush and corresponding crankshaft stub that ran it wearing. The new design no longer relied upon the close tolerance between plain bush and crankshaft, instead oil was fed through oilways in the crankcase to the end of the mainshaft, giving a much more reliable oil supply to the big end bearing.
To make the most of this new arrangement, a new two-piece crankpin with an increased diameter of 1 5/16 inch and a new conrod was used.
The original bush material had changed a number of times over the years in the quest for maintaining good oil pressure to the big end bearing, but none had really fully answered the problem of the bush and corresponding crankshaft stub that ran it wearing. The new design no longer relied upon the close tolerance between plain bush and crankshaft, instead oil was fed through oilways in the crankcase to the end of the mainshaft, giving a much more reliable oil supply to the big end bearing.
To make the most of this new arrangement, a new two-piece crankpin with an increased diameter of 1 5/16 inch and a new conrod was used.
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A change to the colour scheme for 1961 (Silver Sheen and black) came in the way of a two-tone petrol tank with a black top half and Silver Sheen lower. |
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For 1962, UK models retained the previous year's livery whilst Flame, Silver Sheen and black came in for all overseas markets. The petrol tank being Flame top and Silver Sheen lower. |
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The T20J Junior Cub once again mirrored all the changes to the standard T20 Cub except for the fitting of a 9.5mm Zenith carburettor.
Specifications for 1961/62 T20 model
Engine
Type: Single-cylinder OHV, unit construction
Capacity: 199cc (12.1 cu in)
Bore/Stroke: 63mm (2.480in) x 64mm (2.520in)
Compression: 7:1
Power: 10bhp (7.5 kW or 10.1 PS) @ 6000 rpm
Carburettor: Zenith 18MXZ-CS5 or Amal 32/1 (Zenith 9.5mm MXZ for T20J)
Camshaft: Standard - valve clearances In & Ex 0.010in (cold)
Clutch: Wet multiplate
Gears: 4
Cycle Parts
Front Suspension: Telescopic forks, hydraulic damped
Rear Suspension: Swing-arm
Front Wheel: 17 inch (WM2 rim)
Rear Wheel: 17 inch (WM2 rim)
Front Tyre: 3.25 x 17
Rear Tyre: 3.25 x 17
Brakes: 5.5 in dia. Single leading shoe drum front and rear
Petrol Tank: 3 gallons (13.5 litres)
Oil tank - 2 3/4 pints
Gearbox - 1/3 pint
Primary chaincase - 1/3 pint
Front Fork - 1/8 pint
Electrics
Type: Lucas Ignition Coil
Voltage: 6
Charging Type: Alternator / Rectifier
Ignition Timing: 4 degrees BTDC static. 28 degrees fully advanced
Points Gap: 0.014in - 0.016in
Spark Plug: Champion L7 or equivalent
Spark Plug Gap: 0.025in
Specifications for 1961/62 T20 model
Engine
Type: Single-cylinder OHV, unit construction
Capacity: 199cc (12.1 cu in)
Bore/Stroke: 63mm (2.480in) x 64mm (2.520in)
Compression: 7:1
Power: 10bhp (7.5 kW or 10.1 PS) @ 6000 rpm
Carburettor: Zenith 18MXZ-CS5 or Amal 32/1 (Zenith 9.5mm MXZ for T20J)
Camshaft: Standard - valve clearances In & Ex 0.010in (cold)
Clutch: Wet multiplate
Gears: 4
Cycle Parts
Front Suspension: Telescopic forks, hydraulic damped
Rear Suspension: Swing-arm
Front Wheel: 17 inch (WM2 rim)
Rear Wheel: 17 inch (WM2 rim)
Front Tyre: 3.25 x 17
Rear Tyre: 3.25 x 17
Brakes: 5.5 in dia. Single leading shoe drum front and rear
Petrol Tank: 3 gallons (13.5 litres)
Oil tank - 2 3/4 pints
Gearbox - 1/3 pint
Primary chaincase - 1/3 pint
Front Fork - 1/8 pint
Electrics
Type: Lucas Ignition Coil
Voltage: 6
Charging Type: Alternator / Rectifier
Ignition Timing: 4 degrees BTDC static. 28 degrees fully advanced
Points Gap: 0.014in - 0.016in
Spark Plug: Champion L7 or equivalent
Spark Plug Gap: 0.025in