1976 TRIUMPH BONNEVILLE


1976 Triumph T140 Bonneville 750, Triumph motorcycles

The 1976 Triumph Bonneville is the first to adopt left-side shift. Note shifter coming out of primary case.




SPANISH AMALS?
Engine mods were few. A new muffler set were now almost cylindrical reverse-cones (very little taper) & noise reduction revisions. The twin 30mm Amal Concentric carburetors were now being produced by the company's Spanish subsidiary & now featured longer ticklers. New petcocks were now clearly marked with 'ON' and 'OFF' to meet new US regs. To mute intake noise, silencer tubes were installed in the centers of each air filter.

1976 Triumph Bonneville gauges, Triumph motorcycles, motorcycle speedometer

LEFTHAND SHIFT: IT AIN'T RIGHT!
But the biggest change on the 1976 Triumph Bonneville surely was the switch from right-hand shift (the way it traditionally had always been on virtually all foot-shift British & European motorcycles, as well as Sportster; and the way God intended it to be) to left-hand shift again to meet US legislation. This was accomplished with a cross-over shaft, crooked to clear the clutch, which extended through the gearbox and into the center of the primary case, between the clutch & the engine sprocket. From there it passed through the primary cover (a new piece) where it mounted the shifter on its splined end. This all required new inner & outer gearbox covers, bushings, gearbox quadrant, kickstart shaft & primary cover. Many thought it ruined the look of the bike. That beautifully sculpted primary cover was now marred by a shift pedal & the gearbox cover on the other side was conspicuously lacking. It just didn't seem right.

1976 Triumph T140 Bonneville 750, Triumph motorcycles

While color is not correct on this 1976 Triumph Bonneville, it shows the revised transmission cover on the right side of the bike, now missing the shifter.




REAR DISK BRAKE
When the shifter moved to the left, the brake pedal moved to the right. Rather than work up a new linkage for the rear brake, Triumph took this opportunity to introduce a hydraulic disk brake. The underslung Lockheed caliper was operated via a remotely-operated master cylinder hidden under the seat. Both front & rear disk brakes were identical 10" cast iron units (the front slightly thinner than before & sans the chrome plating).

FRAME
Frame modifications were restricted to those needed to accomodate the new rear disk brake & right-hand brake. While regs were heating up in the US, this same year the UK dropped its age-old requirement for a front license plate on motorcycles, the typical ones you saw on front fenders. So the front fenders were no longer drilled for them. Switchgear was now labeled, with the lefthand control displaying cast-in labels, while the righthand control & the headlight shell had cheesy stick-on labels that fell off.

NEW COLORS
The Meriden Co-op struggling as they were just to get the assembly line rolling again, very few changes were made unless absolutely necessary to meet pending regs. Hence the color combos remained as they were in 1974 & 1975, for part of the year & Photochromatic Red & Cold White for US & UK markets and also Photochromatic Blue & Cold White as a UK option. But gone was the 650cc T120, after 25 years of service, only the 750cc T140 remained.

1976 Triumph T140 Bonneville, Triumph motorcycles

This 1976 Triumph Bonneville got British-spec Polychomatic Blue & Cold White paint.


1976 Triumph Bonneville SPECIFICATIONS:



MODEL DESIGNATIONS:
1976 Triumph Bonneville T140V..................... 750cc

ENGINE:
Engine type....................................... OHV vertical twin
Horsepower at RPM............................ 49 BHP @ 6,200 rpm
Bore................................................ 76mm / 2.79"
Stroke............................................. 82mm / 3.23"
Displacement.................................... 744cc / 40 cu. in.
Compression Ratio............................. 8.6:1
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.......................... 55 degrees BTDC
Exhaust Valve Closes.......................... 27 degrees BTDC

IGNITION:
Ignition Breaker Gap............................. 0.4mm / 0.015"
Spark Plug Gap.................................. 0.50mm / 0.020"
Timing (static).................................14 degrees BTDC
Timing (fully advanced):........................ 38 degrees BTDC

CARBURETORS:
Type................................................ Amal Concentric
Throat Size....................................... 30mm
Main Jet........................................... 210
Needle Jet........................................ .107
Needle Position.................................. 2
Needle Type.......................................D
Throttle Valve.................................... 2
Pilot Jet............................................ 25

TRANSMISSION:
Speeds.............................................. 4
Gear Ratios:
5th - Top........................................... 4.7
4th - Fourth........................................ 5.59
3rd - Third......................................... 6.58
2nd - Second...................................... 8.63
1st - Bottom...................................... 12.25

CLUTCH:
Type................................................ Multi-plate, wet
Number of Plates:
Drive Plates...................................... 6
Driven Plates.................................... 6

SPROCKETS:
Engine............................................. 29 teeth
Clutch............................................. 58 teeth
Gearbox.......................................... 20 teeth
Rear Wheel...................................... 47 teeth

CHAIN:
Primary, pitch.................................. 3/8" triplex
Primary, length................................. 84 links
Final Drive, pitch............................... 5/8" X .400" X 3/8"
Final Drive, length............................. 106 links

CAPACITIES:
Fuel (US versions)............................. 2.5 Imp. gal.
Fuel (UK & export versions)................. 4 Imp. gal.
Oil Tank........................................... 5 pints / 3 L
Gearbox........................................... 1 pt / 500cc
Primary Chaincase............................. 1/4 pt / 150cc
Front Forks....................................... 6.4 oz. / 190cc

TIRES:
Front............................................... 3.25 X 19"
Rear................................................ 4.00 X 18"

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

BRAKES:
Front............................................... 10" / 12.9cm disk
Rear................................................ 7" / 17.78cm SLS

DIMENSIONS:
Seat Height...................................... 32.5" / 77.5cm
Wheelbase........................................ 54.5" / 140.3cm
Length.............................................. 85.5" / 202cm
Width............................................... 28.5" / 72cm
Ground Clearance.............................. 5" / 12.7cm
Weight, unladen................................ 387 lbs / 176kg


SAVE THE BONNEVILLE!
Did you ever wonder what really happened to Triumph? This is the behind-the-scenes story of the Meriden Workers' Co-op, written by John Rosamond, the welder-turned-Company Chairman. From the factory takeover in '73, and the formation of the Co-op in '75, through their endless struggles to continue to produce Triumph Bonnevilles, despite constant setbacks & opposition, until its slow death in 1983. The book is loaded with amazing photos & information you won't find anywhere else. This is not hearsay either, this is the real deal right from the source. I lived through this stuff myself, working as an apprentice mechanic in a Triumph/BSA/Norton dealership in 1971 when the first Oil-in-Frame Triumphs arrived to a lukewarm response. There were lots of ups & unfortunately more downs for the cash-strapped Co-op, but the scrappy Brits soldiered on & even came out with some stunning new models (like the Diana watercooled DOHC 4-valve twin, the contra-rotating balance shaft Bonneville, the 8-valve TSS, Anti-Vibration frames with rubber engine mounts & more), all outlined in the book. It's a MUST READ for anyone who mourns the loss of the British Motorcycle Industry as a whole & of Triumph in particular.


You can order the book by clicking on the picture of the book cover, above.


TRIUMPH MOTORCYCLE BOOKS


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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