1962 TRIUMPH BONNEVILLE


1962 Triumph T120 Bonneville 650, Triumph motorcycles, Triumph TR6, Triumph Thunderbird



MODEL DESIGNATIONS
The 1962 Triumph Bonneville again came in two basic model designations: T120R was the Road version, and T120C was the Sreet Scrambler/Off-Road version (what later might have been called an Enduro). Most of the bike was strictly carry-over from 1961. Of course, this was the last year for the non-unit construction engine and the duplex frame, the same applied to its sister-bike, the Triumph TR6. So, Triumph Motorcycles did little development work to this 'lame duck' model. All the money, time and engineering was being poured into the new-for-1963 Unit-Construction 650.

TRYING TO ACHIEVE BALANCE
For the 1962 Triumph Bonneville, most of the development work was aimed at quelling vibration, which with the added power of the twin-carb Bonnie, was beginning to be a real problem. Starting with Engine #K15789, the crankshaft balance factor was juggled again, from 50% back up to 71% (it had been dropped from 70% to 50% in 1959 in an effort to curb vibration). Then, starting with Engine #D17043, the balance factor was changed again to 85%, and an entirely new crankshaft was introduced, with 'pear-shaped' webs. The new crank was heavier, and while it may have helped reduce vibration slightly, it was at the cost of acceleration.

Triumph Bonneville, Triumph TR6, Triumph motorcycles, Triumph motorcycle tank

1962 Triumph Bonneville engine & gearbox from the timing side. Notice the open carbs (no filters) & the woven spark plug wires leading to either side of the magneto.



FUEL SYSTEM
While the carburetors remained the same, a new petcock arrangement allowed both carbs to be fed by either petcock. As it turned out, to capture the full performance of the 1962 Triumph Bonneville 650 engine, both petcocks still needed to be open to supply enough fuel to both carbs on full boil. The only other change to the powerplant was a slightly higher 3rd gear ratio.

THE SAME, BUT DIFFERENT
Again, as always, the 1962 Triumph Bonneville was the twin-carb version of the Triumph TR6, albeit with different paint colors.

ELECTRICS
The American-market T120Cs got a more waterproof "Wader' version of the Lucas K2FC auto-advance magneto. A new Lucas RM19 alternator also made its debut, while retaining the previous lower-output stator to minimize bulb failure and battery overcharging. The horn was also changed to a Type H8.

1962 Triumph Bonneville, Triumph Motorcycles, Triumph TR6

Gauge cluster (clocks) on a 1962 Triumph Bonneville T120.



NEW COLORS
The biggest differences between the 1962 Triumph Bonneville and the 1961 it replaced (aside from the vibration-abatement measures), was the appearance of the motorcycle. The seat was now 2-tone, with a gray panel on the top surface and along the bottom edge, with black on the sides and back. And the color was a big switch from the pale blues of the past couple of years. For 1962, all Triumph Bonnevilles were painted Flame and Sliver Sheen. Flame, which is very orange, was on the top and Silver on the bottom, separated as before by a gold pinstripe.

LAST OF THE PRE-UNITS
The 1962 Triumph Bonneville marked the end of an age. It was the last non-unit construction motorcycle built by Triumph. Unit construction ushered in the modern age, or so it must have seemed at the time. Little did they know that just a few short years from then, the Japanese would flood the market with technologically advanced machinery the likes of which the world had never seen!

1962 Triumph T120 Bonneville 650 engine, Triumph motorcycles, Triumph TR6, Triumph Thunderbird

1962 Triumph Bonneville 650 engine. Last of the Pre-Units.


1962 Triumph Bonneville SPECIFICATIONS:



MODEL DESIGNATIONS:
1962 Triumph Bonneville T120C..................... Scrambler
1962 Triumph Bonneville T120R..................... Roadster

ENGINE:
Engine type....................................... OHV vertical twin
Horsepower at RPM............................ 46 BHP @ 6,500 rpm
Bore................................................ 71mm / 2.79"
Stroke............................................. 82mm / 3.23"
Displacement.................................... 649cc / 40 cu. in.
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

IGNITION:
Magneto Point Gap............................. 0.3mm / 0.120"
Spark Plug Gap.................................. 0.50mm / 0.020"
Timing (fully advanced):
Crankshaft position............................. 39 degrees BTDC
Piston position................................... 11mm / 7/16" BTDC

CARBURETORS:
Type................................................ Amal Monobloc
Throat Size....................................... 1-1/16"
Main Jet........................................... 240
Needle Jet........................................ .1065
Needle Position.................................. 2
Throttle Valve.................................... 376 / 3-1/2
Pilot Jet............................................ 25

TRANSMISSION:
Speeds.............................................. 4
Gear Ratios:
4th - Top........................................... 4.88
3rd - Third......................................... 5.81
2nd - Second...................................... 8.25
1st - Bottom...................................... 11.9
RPM @ 10MHP in Top Gear................... 638 RPM

CLUTCH:
Type................................................ Multi-plate, wet
Number of Plates:
Drive Plates...................................... 6
Driven Plates.................................... 5
Friction Material................................ Neolanglite

SPROCKETS:
Engine............................................. 22 teeth
Clutch............................................. 43 teeth
Gearbox.......................................... 18 teeth
Rear Wheel...................................... 43 teeth

CHAIN:
Primary, pitch.................................. 1/2" X .335" X 5/16"
Primary, length................................. 70 links
Final Drive, pitch............................... 5/8" X .400" X 3/8"
Final Drive, length............................. 101 links

CAPACITIES:
Fuel (US versions)............................. 3 Imp. gal.
Fuel (UK & export versions)................. 4 Imp. gal.
Oil Tank........................................... 5 pints / 3 L
Gearbox........................................... 2/3 pt / 400cc
Primary Chaincase............................. 1/4 pt / 150cc
Front Forks....................................... 1/4 pt / 150cc
TIRES:
Front............................................... 3.25 X 18"
Rear................................................ 4.00 X 18"

SUSPENSION:
Front............................................... Telescopic Forks
Rear................................................ Swing Arm

BRAKES:
Front............................................... 8" / 20.32cm SLS
Rear................................................ 7" / 17.78cm SLS

DIMENSIONS:
Seat Height...................................... 30.5" / 77.5cm
Wheelbase........................................ 54.5" / 140.3cm
Length.............................................. 85.5" / 202cm
Width............................................... 28.5" / 72cm
Ground Clearance.............................. 5" / 12.7cm
Weight, unladen................................ 393 lbs / 178kg


TRIUMPH MOTORCYCLE BOOKS


TRIUMPH RESTORATION, PRE-UNIT TALES OF TRIUMPH & MERIDEN

TRIUMPH MOTORCYCLES: TRIUMPH ENGINEERING CO.

TRIUMPH WORKSHOP MANUAL, 1935-1939

TRIUMPH WORKSHOP MANUAL, 1937-1951

TRIUMPH WORKSHOP MANUAL, 1945-1955

TRIUMPH MOTORCYCLES: FROM SPEED TWIN TO BONNEVILLE

TRIUMPH MOTORCYCLES - HINKLEY RENAISSANCE

SAVE THE TRIUMPH BONNEVILLE

THE INSIDE STORY OF THE MERIDEN WORKERS' CO-OP.
STORY OF THE TRIUMPH BONNEVILLE - MOVIE

TRIUMPH 650 & 750 TWINS

ESSENTIAL BUYERS GUIDE TO TRIUMPH BONNEVILLE

TR BONNEVILLE 2001-08

TR BONNEVILLE, PORTRAIT OF LEGEND

TR BONNEVILLE: T120/T140

TRIUMPH MC RESTORATION

HAYNES TR TRIPLES & FOURS

TRIUMPH 21 TO DAYTONA

TRIUMPH TIGER CUB BIBLE

Triumph Motorcycles
Triumph Bonneville
Triumph Bonneville, Pre-Unit Construction, 1959-1962
Triumph Bonneville, Unit Construction, 1963-1970
Triumph Bonneville, Oil-in-Frame, 1971-1983

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