Triumph TR7

By 1973, Triumph Motorcycles was in serious trouble. Parent company BSA had managed to ‘snatch failure from the jaws of success,” taking Triumph from incredible success in the late 1960s to the brink of insolvency by 1971. Through bad management, questionable backroom dealings (Jack Sangster sold off all the company assets at bargain-basement prices) and the onslaught of the Japanese (mainly Honda), Triumph suddenly found itself woefully outclassed by its rivals. Throughout the 1960s, the hot Triumph 650 twins, the T110 Tiger, the TR6, and the twin-carb legend Bonneville were widely-regarding as the fastest motorcycles a ‘normal person’ could buy (ie: not expensive like a Vincent Black Shadow), the superbikes of their day. Then the Honda 750 Four arrived, and suddenly the old vertical twins were losing their relevance. BSA not-so-quickly responded in 1971 with a whole new range of 650 twins, for which they designed virtually everything new except that one major component that needed changing: the engine. Instead, they created an entirely new all-welded steel double front downtube frame which carried the engine oil in its large-diameter backbone/seat post. There were new forks, new wheels & brakes, new bodywork, switchgear, the works. However, the 3 major things the bike really needed to be competitive with the Japanese were painfully absent: Electric start, 5-speeds & a front disk brake.

The 1971 Triumph TR6 launched amid major design & development problems – the engine wouldn’t fit in the new frame! The entire top end needed to be redesigned to make it work. That wasn’t all; the seat height was over 34 inches, too tall for most riders. It took until the 1973 model year for Triumph to sort out what was now called the Triumph TR6 Tiger.

In 1973, the Triumph twins & Triples (ie: Triumph Trident) finally got 5-speed transmissions & a front disk brake. 5-speeds had been optional since 1971, but were now standard across the line. While the 649cc TR6 Tiger remained, a new punched-out version was introduced called the TR7 750 Tiger. In fact, these early machines were bored from 71mm out to 75mm for a displacement of 724cc. However, later in the 1973 model year, a new cylinder casting made it possible to increase the bore again to 76mm for a displacement of 744cc. The 82mm stroke remained unchanged on all models.

Starting in 1971, all single-carb 650 & 750 twins were called “Tigers”. Other than a brief one-year appearance in 1960, when the name TR7 was used to describe left-over 1959 Triumph Bonnevilles that were being sold alongside 1960 Bonnevilles. Otherwise, the TR7 name didn’t appear again until the 1973 model year as the big-bore single-carb Tiger, as the TR7P (Police) & the TR7RV (Roadster w/5-speed). Early-1973 724cc Triumph TR7RVs had engine & frame numbers running from KH17122 to XH21715. Later 1973 TR7P Police bikes with 744cc ran from GH35388 to GH35466. And the 744cc TR7RVs ran AH23727 to GH35387. From Model-Year 1974 until its demise in 1983, the only single-carb big twins were the Triumph TR7 Tiger, gone forever was the TR6 (with one exception: in 1983, the final year of Triumph production, one last 650 was briefly built under the name Triumph TR65, meant to be an entry-level version.)

ABOVE: What’s missing here? Oh yeah, the shifter! This 1976 Triumph TR6 was the first year for left-foot shift. Heresy of heresies!!
While the twin-carb Bonneville always stole the spotlight, the single-carb 750 Triumph TR7 and its 650 TR6 predecessor was judged by many to be the better bike. While producing marginally less horsepower at max rpm, in real-world practical terms, the Tiger was just as fast at the Bonnie. And the single carburetor delivered much better drivability at low speeds. Two cylinders breathing through one throat makes for higher vacuum & more even pulses, both very good for carburetors. So they pull harder at low engine speeds & in the higher gears when vacuum usually drops. This becomes even more pronounced when you raise your final gearing (lower numerical ratio, ie: smaller rear sprocket). And of course one carb is always easier to tune than two. I’ve had both, and while people love looking at those twin carbs, the TR7s usually ran better.


1973 TR7 Tiger 750

First year for the 750, first year for the 5-speed as standard equipment & first year for the front disk brake. Finally sorted out the new “oiler” frame & running gear & it was becoming a very fine machine.


1976 TR7 Tiger 750

A year of firsts: The first left-shift, the first rear disk brake & the first bikes built by the new Meriden co-op.


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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