Triumph Bonneville Oil-in-Frame
1971 through 1983


TRIUMPH BONNEVILLE OIL-IN-FRAME
WHAT HAPPENS AFTER THE BONNEVILLE PEAKS?

As the 1960's came to a close, Triumph motorcycles were both at the top of the world, and at the edge of a precipice. The 60's had been good to Triumph, the Triumph Bonneville holding the title of world's fastest production motorcycle for most of it, until the arrival of the Honda 750-Four in 1969. But, the Triumph Bonneville, and and the Triumph TR6 also, enjoyed roaring success throughout the decade and as the 1970 model year ended, the Triumph 650 twin was really at it's zenith. It was about as fast and as good as it ever would be again. And it was still a top-seller. But that was all about to change.

BSA BUMBLING
On top of all the other challenges facing Triumph motorcycles, their parent company, BSA Motorcycles, once the largest motorcycle producer in the world & a true corporate giant, was now out of money & had been run very poorly since Edward Turner's retirement in 1963. Despite being in direct competition with them, throughout the 1950s BSA had always stayed out of Triumph's way, but by the late 1960s BSA had become very involved in Triumph's affairs, including the design of its motorcycles.


UMBERSLADE HALL DEBACLE
At a time when scarce resources should have been devoted to developing new, more modern products, BSA spent vast sums of money turning an Olde English country estate called "Umberslade Hall" into their new "Technology Center", from which all the great new designs would come that would save the company.

BAD PLANNING, AS USUAL
Like everything else BSA did during this era, it was badly planned & executed, it cost too much, took too long & didn't yield the anticipated benefit. Money, time and engineering talent were lavished projects like the ill-fated BSA 350 Bandit/Triumph 350 Fury, but little good came of it.

MUCH IS NEEDED...
Considering the daunting competition pouring out of Japan at that time, the Triumph Bonneville needed many things. Principal among these were a front disk brake, a 5-speed & an electric starter. Problems of vibration, poor electrics, oil leaks & spotty build-quality also needed to be addressed, as the buying public became accustomed to the trouble-free service they had come to expect from Honda.

...LITTLE IS DONE
How did the new "think tank" at Umberslade Hall respond to this? Of all the things the Triumph 650 didn't need, it was a new frame, but that's exactly what it got. And true to BSAs management style, it cost too much, took too long, was badly designed & executed, and didn't accomplish the updating that the Triumph Bonneville needed so badly. For some unknown reason, BSA assigned this crucial redesign to a group of mostly aeronautical engineers who had no experience & little interest in motorcycles. And so, the Triumph Bonneville Oil-in-Frame wa born.

MORE SCREW UPS
As a result, it took so long to get the blueprints finalized that the production line at Meriden sat idle for weeks. When the first frames were finally built, it was discovered that the engines wouldn't fit in the frames on the assembly line. A quick redesign of the head & rocker boxes made it work, adding to the cost & delay, but this was indicative of how screwed up the BSA organization was.

NEW BIKE IS DISAPPOINTING
What was finally released (late) as the 1971 650 Triumph Bonneville oil-in-frame was not well-received, and never sold very well again after that. However, what was accomplished was still very comprehensive and, because of that, impressive. A completely new oil-bearing frame, new front forks & yokes, new wheels & brakes front & rear, new exhaust, and for better or worse, a new look.

ALL NEW FRAME & RUNNING GEAR
The 1971 Triumph Bonneville oil-in-frame and TR6 (also oil-in-frame) got an entirely new one-piece, all-welded steel frame that held the engine oil in its huge 3" diameter backbone, instead of in a separate oil tank, as before. Great idea in concept, but somehow the boys at Umberslade Hall couldn't figure out how to keep the oil from foaming & so relocated the oil filler cap from just behind the steering head to just under the nose of the seat, lowering the oil level & abandoning all that internal volume in the large portion of the backbone under the tank. So this enormous 'drain pipe' of a backbone that was supposed to be filled with oil was now filled about halfway, leaving the new bike woefully in short supply. Another big problem with the new Triumph Bonneville oil-in-frame was that it raised the seat height to 32-1/2", too tall for many riders.
COOL NEW CONICAL HUBS
The new front forks weren't too bad, they now had aluminum sliders. The first two years of the Oil-in-Frame family of Triumph Twins sported a 8" TLS (Twin Leading Shoe) front brake in a very cool-looking conical hub & an even cooler looking front air scoop. While it worked adequately enough (after some initial teething problems), one might ask why BSA spent the money developing this new brake when it would soon be replaced with a disk brake.

OILERS TURNED INTO GOOD BIKES
Despite all the controversy, poor sales & the initial 'shake-down' problems, the Triumph Bonneville Oil-in-Frame continued to be developed & refined, and actually became very fine motorcycles in their own right. While never any real competition for the new superbikes coming out of Japan, the Triumph Bonneville Oil-in-Frame endured on through even more upheaval and controversy on its rocky way to the end of Triumph Motorcycles in 1983.

AT LAST, A 5-SPEED!
Late in 1972, the trusty Triumph 650 got a much-needed 5-speed transmission, as an option at first then as standard, and the seat height was dropped back down to 30". In 1973, the front disk brake finally arrived & the 650 was bored out to a 750. Model designations changed accordingly: the Triumph Bonneville T120 became the T140; and the Triumph TR6 became the TR7. Very few bikes were built in 1974 and none in 1975 because of an employee lock-out of the Meriden factory. 1976 saw the shifter move to the left side of the bike & a disk brake on the rear. By this time, the single-carb versions had been dropped, in 1975 the last Trident was built (T160), so the only motorcycle that the Meriden Co-op produced was the Triumph Bonneville oil-in-frame.

SPECIAL EDITIONS
Throughout the rest of its life, Triumph Motorcycles tried to boost sales (its one-and-only product now the Triumph Bonneville Oil-in-Frame) by developing several Special Edition Triumph Bonnevilles, such as the Silver Jubilee of 1977, the Bonneville Special of 1979, the TSS & the Royal Wedding Edition (celebrating the wedding of Prince Charles to Lady Diana Spencer) of 1982, and the 'too-little-too-late" 4-valve-per-cylinder TSX of 1983.

THE END IS NEAR
Despite their best efforts, sales remained slow throughout the entire lifespan of the Oil-in-Frame Triumphs. Certainly not enough sales were being made to turn around BSA's, and then later Norton-Villiers' fortunes. 1983 was the end of classic Triumph Bonneville oil-in-frame production. It was the end of an age.

TRIUMPH BONNEVILLE OIL-IN-FRAME
GREAT BIKES CHEAP

The good news is that most of these Oil-in-Frame bikes are not yet considered to be collectable, at least not on par with the 1970-and-earlier bikes, so they can be picked up fairly cheap & they make the best riders. If you're planning on buying a classic Triumph motorcycle to ride, then an "Oiler" (in this case, a Triumph Bonneville Oil-in-Frame) might be the way to go. Most are 5 speeds with disk brakes & can be made into very nice machines. I know, I rode my 1973 T140 Triumph Bonneville custom cafe racer all over California.

NEW BONNEVILLES
The other good news is that a few years after the 1983 collapse, English businessman John Bloor bought what was left of Triumph motorcycles, which was little more than the rights to the name at that point. He reopened Triumph a few years later & now builds stunning, state-of-the-art new Triumphs that are good enough to compete with motorcycles built anywhere.



Triumph Bonneville Oil-in-Frame
YEAR-BY-YEAR


1971 TRIUMPH BONNEVILLE
650cc: T120

First year for Triumph Bonneville Oil-in-Frame. Major redesign of everything except the engine. New oil-bearing frame, forks, conical hubs F&R & a whole new look + 34-inch seat height. Not well-received.


1972 TRIUMPH BONNEVILLE
650cc: T120 (4-speed)
650cc: T120V (optional 5-speed)

Seat height dropped to 32-1/2" with mods to rear frame & ancillaries. 5-speed Quaife gearbox now optional. New head w/push-in exhaust headers.


1973 TRIUMPH BONNEVILLE
650cc: T120V
750cc: T140V

650 Triumph Bonneville Oil-in-Frame bored out to 750 w/new 10-bolt head, 5-speed gearbox standard & (at long last) a 10" front disk brake.


1974 TRIUMPH BONNEVILLE
650cc: T120V
750cc: T140V

Production halted early in model year due to employee shut-down of factory. Very few '74s are built. They are essentially the same as '73.




1975 TRIUMPH BONNEVILLE
750cc: T140V

Meridian factory, where all Bonnevilles were built, shut down for most of the 1975 model year. Some '74s locked up during strike were sold as '75s. 650cc T120 dropped.



1976 TRIUMPH BONNEVILLE
750cc: T140V

Meridian factory, where all Bonnevilles were built, shut down for most of the 1975 model year. Some '74s locked up during strike were sold as '75s. 650cc T120 dropped.



1977 TRIUMPH BONNEVILLE
750cc: T140V
750cc: T140VJ Silver Jubilee Edition

Largely carryover from '76. Triumph builds its first "special", the Silver Jubilee Edition celebrating Queens 25-year reign. Garish colors, not a big seller.


1978 TRIUMPH BONNEVILLE
750cc: T140V
750cc: T140E (Environmental)

New T140E joins T140V mid-year, designed to meet new smog regs. New head w/parallel intake ports & Amal MkII carbs.



1979 TRIUMPH BONNEVILLE
750cc: T140E
750cc: T140D (Special)

T140D Bonneville Special w/Lester mag wheels sold alongside T140Es. Negative-ground electrics & 3-phase alternator added in prep for next year's electric starter.



1980 TRIUMPH BONNEVILLE
750cc: T140E
750cc: T140D (Special)
750cc: T140ES (Electric Start)

Finally, the Bonneville gets an electric starter! It drives off the intake cam gear & has a modified timing cover. Rear brake caliper is mounted above the swing arm.


1981 TRIUMPH BONNEVILLE
750cc: T140E (kickstart)
750cc: T140ES (Electric Start)
750cc: T140E & ES (Executive)
750cc: T140AV (Anti-Vibration)

Bonneville Executive touring bike is released. Twin front disks available with Morris cast alloy wheels.



1982 TRIUMPH BONNEVILLE
750cc: T140E (kickstart)
750CC: T140ES (elec start)
750cc: T140LE (Royal Wedding)

New Italian tank. Optional twin front disks. Bing CV carbs in US. T140LE Royal Wedding celebrates Charles & Diana'a wedding.


1983 TRIUMPH BONNEVILLE
750cc: T140E (kickstart)
750cc: T140ES (electric start)
750cc: TSS (4-valve engine)
750cc: TSX (factory custom)

Last year of Meriden Triumphs. TSX custom gets 16" rear wheels & wild stickers. TSS has new top end w/4 valves per cylinder.



1982-83 TRIUMPH T140W TSS
Triumph's last gasp. Westlake top end gave it 4 valves-per-cylinder & 58 hp. Fast, smooth, but too little too late. Few were built.







1985-88 LES HARRIS BONNEVILLE
750cc: T140ES

After Triumph closes doors, Les Harris buys rights to produce Triumph Bonnevilles for next 3 years from John Bloor, who had himself purchased Triumph. In just over 3 years, Harris builds 1,255 bikes w/Italian ancillary parts.



NEW VIDEO:
"TRIUMPH BONNEVILLE THRU THE YEARS"

Take a video walk through every year of classic Triumph Bonneville, from 1959 to 1983. All are taken from the same camera angle to provide some continuity.


MORE TRIUMPH BONNEVILLES:
Triumph Bonneville
Triumph Bonneville Pre-Unit (1959-1962)
.....1959
.....1960
.....1961
.....1962
Triumph Bonneville, Unit-Construction(1963-1970)
.....1963
.....1964
.....1965
.....1966
.....1967
.....1968
.....1969
.....1970
Triumph Bonneville, Oil-in-Frame
.....1971
.....1972
.....1973
.....1974
.....1975
.....1976
.....1977
.....1978
.....1979
.....1980
.....1981
.....1982
.....1983
Les Harris Bonnevilles(1983-1989)
OTHER TRIUMPHS:
Triumph TR6
Triumph TR7
Triumph Trophy
Triumph Tiger
Triumph Thunderbird
Triumph Trident
Triumph X-75 Hurricane


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)

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