1979 Triumph T140D
Bonneville Special

MY 1979 TRIUMPH T140D BONNEVILLE SPECIAL
I own a '79 T140D myself. It's pictured above, on display at the Quail Motorcycle Gathering in Carmel CA in 2011. The day after this show I rode it in the Quail Ride, which took us through the hills around Carmel. It happened to be my birthday, and what a day! The T140D ran flawlessly, I was in the company of an eclectic collection of classic bikes, perfect weather, great riding country, nice folks...happy birthday to me.
1979 TRIUMPH 140D BONNEVILLE SPECIAL
Triumph did one of its best cosmetic redux of the classic T140 Bonneville, but it wasn't purely cosmetic. The 1979 Triumph T140D Bonneville Special, as it was named, featured not only the Jubilee’s upside-down shocks, a two-into-one exhaust header, and Morris mag wheels. Unfortunately, any potential power gains were more than muted by the new ‘smogger’ cylinder head and Amal Mk II carburetors, designed to reduce emissions. Compression was reduced to just 7.9:1 in an attempt to reduce engine vibration. All 1979 Bonnevilles got the new head and carbs, along with Lucas’s new ‘Rtia’ electronic ignition system. The 1979 and 1980 T140D Bonneville Special was differentiated from run-of-the-mill T140E Bonnevilles by it’s all-black paint paint scheme with gold pin stripes, the 2-into-1 exhaust, and a set of stunning Morris mag wheels. I actually own one (pictured above), and they’re decent bikes to ride. The stepped seat isn’t all that comfy, they don’t have much power, and the smog-era carbs are finicky, both to tune and to ride. The 2-into-1 header sounds like crap, I like the sound of dual pipes much better. But, it was a handsome machine, and it did fairly well in the marketplace at the time, ringing the bell for Triumph yet again. There certainly are a lot of T140D running around today, I see them at auctions and shows all the time.
ABOVE: A rare color combo, blue and silver was available on the 1979 Triumph T140D Bonneville Special, but few were done so.
(Photos courtesy of MidAmerica Auctions.)

1979 Triumph T140D Bonneville Special SPECIFICATIONS

T140D Bonneville

Engine type

Displacement

Bore & Stroke

Compression

Carburetors

Ignition

Engine output

Primary drive

Primary sprockets

Clutch

Gearbox

Ratios, overall:

1st, bottom

2nd

3rd

4th

5th, top

Final drive

Final drive sprockets

Frame type

Suspension, front

Suspension, rear

Brake, front

Brake, rear

Tire, front

Tire, rear

Fuel capacity

Wheelbase

Seat height

Ground clearance

Weight

5-speed 750 Bonneville Special

Air-cooled OHV vertical twin

744cc / 45.0 ci

76mm X 82mm / 2.99" X 3.23"

7.9:1

2- Amal Concentrics MkII, 30mm

Battery & coil, Lucas

49 bhp @ 6200 rpm

3/8" triplex X 84 links

Engine 29T X Clutch 58T

Multi-plate, wet

5-speed constant-mesh, left-foot shift


12.25:1

8.63:1

6.58:1

5.59:1

4.7:1

5/5" X .400" X 3/8" chain X 106 links

Gearbox 19T X Rear 47T

All-welded, oil-bearing large-tube backbone

Telescopic fork, hydraulic damping 2-way

Swing arm, 2 Girling dampers

10" disk, 2-piston hydraulic caliper

10" disk, 2-piston hydraulic caliper

3.25" X 19" Dunlop, ribbed

4.00" X 18" Dunlop, universal

3 Imp gal (US) / 4 Imp gal (UK & export)

54.5" / 140.3 cm

32.5" / 77.5 cm

5" / 12.7 cm

395 lbs/ 180 kg


Check out these TRIUMPH BOOKS




2018 Classic Triumph Calendar


Triumph Motorcycles: The art of the motorcycle


The Complete Book of Classic and Modern Triumph Motorcycles 1937-Today (Complete Book Series)


Triumph Motorcycles: From Speed-Twin to Bonneville


Triumph Bonneville and TR6 Motorcycle Restoration Guide: 1956-83


British Motorcycles Triumph (Little Books)


Triumph Motorcycles in America


McQueen's Motorcycles: Racing and Riding with the King of Cool


Triumph Motorcycle Restoration


Illustrated Triumph Motorcycles Buyer's Guide: From 1945 Through the Latest Models (Illustrated Buyer's Guide)


Tales of Triumph Motorcycles and the Meriden Factory


Hinckley Triumphs: The First Generation (Crowood Motoclassic)






Please visit our
MOTORCYCLE BOOK STORE


Take a tour of our site...

HOME PAGE
Triumph Motorcycles
.....Bonneville
.....Tiger
.....Trophy
.....TR6
.....TR7
.....Trident
.....X-75 Hurricane
.....6T Thunderbird
.....5T Speed Twin
.....Daytona
.....Twenty-One
.....3T 350 Twins
BSA Motorcycles
.....A65
.....A10
.....A7
.....Gold Star
.....Bantam
.....Rocket 3
.....B50
Norton Motorcycles
.....Commando
.....Atlas
.....Dominator
.....Model 7
.....Manx
.....Navigator
AMC-Associated Motor Cycles
Matchless-AJS Motorcycles
.....G3
.....G9
.....G12
.....G80
Royal Enfield Motorcycles
.....Interceptor
.....Bullet
Ariel Motorcycles
.....Square Four
.....Red Hunter
.....Cyclone
Vincent Motorcycles
.....Black Shadow
.....Rapide
.....Comet
.....Egli-Vincent
Velocette Motorcycles
.....KSS
.....KTT
.....LE
.....MAC
.....Thruxton
.....Venom
.....LE
Rickman Motorcycles
Japanese Motorcycles
.....Honda
.....Kawasaki
.....Suzuki
.....Yamaha
Cafe Racers
....Triumph Cafe Racers
.....Norton Cafe Racers
.....Other Cafe Racers
Choppers & Bobbers
.....Choppers
.....Triumph Choppers
.....BSA Choppers
.....Rat Bikes
Classic Racing Motorcycles

Classic Motorcycle Events
.....Auctions
.....Shows
.....Rides
Classic Motorcycle Restoration
Classic Motorcycle Shops
Classic Motorcycle Clubs
Send us Pictures of YOUR BIKE
YOUR BIKE Pictures

HOME PAGE
.....About Us
.....Site Map
.....CONTACT US
.....Please visit our BLOG
.....Subscribe to our FREE e-zine BRIT IRON
.....BRIT IRON E-zine Back Issues

Visit our STORES
.....Motorcycle Books
.....Motorcycle Magazines
.....Motorcycle Calendars
.....Motorcycle Accessories
..........Motorcycle Helmets
..........Motorcycle Rain Suits
..........Motorcycle Locks & Security
..........Motorcycle T-Shirts
..........Motorcycle Diecast Models
..........GoPro Cameras
.....Motorcycle Parts
..........Motorcycle Tires
..........Motorcycle Chains
..........Motorcycle Batteries
..........Motorcycle Handlebars
.....Motorcycle Tools
..........Whitworth Tools
..........Tire Tools
..........Chain Tools

Crazy about cars, too? Check out our sister site:
www.American-Muscle-Cars.net


Learn how to BUILD YOUR OWN WEBSITE, like I did.

Back to top - 1979 Triumph Bonneville Special
Updated 9/3/18

BREAKING NEWS:

BSA Starts Production of NEW BSAs



NEW PAGE:
Vintage Motorcycle Pictures



2019
 CALENDARS ARE HERE!



Visit our new
Motorcycle Store

WHITWORTH WRENCH & SOCKET SET



Please visit our
MOTORCYCLE BOOK STORE


Subscribe to your favorite
MOTORCYCLE MAGAZINES



BIKES FOR SALE!
Check out our
FREE
Classifed Ads



NEW SECTIONS:

Motorcycle Racing


THIS MONTH'S FEATURE PAGE:
1977 Triumph Sliver Jubilee

NEW PAGES
added this month:

* 1979 Triumph T140D Bonneville Special
* Motorcycle Racing
* 1964 Matchless G3C
* 1955 BSA Gold Star
* AJS Motorcycles
* Helmet Features 2018
* AJS Motorcycles
* 1961 AJS Model 31
* 1959 AJS Model 16
* 1927 AJS Model H4
* 1959 AJS Model 31 CSR
* 1946 AJS Model 18
* 1964 AJS Model 16
* 1953 AJS Model 18
* 1950 AJS 7R Boy Racer
Enjoy. More coming soon...