Triumph Riddles: 1963-1967 Triumph T120 TT Specials

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Bill Sherman’s collection of Triumph TT Specials showcases every year of TT Special production, starting with the first in 1963 (far right) through the last in 1967 (far left), and every variant in between.
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First-year 1963 TT Special had exhaust mounted high and running down both sides of the bike.
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1963 Triumph T120 TT Special
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Last-year 1967 TT Special exhaust routes down and under the engine, exiting in front of the rear wheel.
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1963 Triumph T120 TT Special
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1963 Triumph T120 TT Special
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TT Special engines were stamped with a “C” from 1964-1966 only.
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The “TT” stamp came mid-1966 and was used to the end of production in 1967.
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First-year 1963 TT Special.
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Second-year 1964 TT Special, still with high pipes.
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Third-year 1965 TT Special, first year for larger exhaust pipes routed under the engine and exiting in front of the rear wheel.
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Fourth-year TT Special featured new crankshaft and 62-degree fork rake versus earlier 65-degree.
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Fifth and final-year TT Special.
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Bill on his 1966 TT Special on the day he uncrated it in 1966!

1963-1967 Triumph T120 TT Specials
650cc OHV parallel twin, 71mm x 82mm bore and stroke. Compression ratio 12:1 (1963)/11:2 (1964/some say 11:1)/11:1 (1965-1967), 52hp @ 6,500rpm
Top speed:
120mph (period test)
Twin 389/95 1-3/16in Amal Monobloc (1963-early 1967)/Twin Amal Concentric (late 1967)
4-speed, chain final drive
Lucas ET Energy Transfer
Single downtube steel cradle/55in (1,397mm)
Telescopic forks front at 65-degree angle (later 62-degree); dual Girling shocks w/adjustable preload
8in (203mm) SLS full width drum front, 7in (178mm) SLS drum rear
3.5 x 19in front, 4 x 18in rear
Weight (dry/approx.):
350lb (159kg)
Seat height:
32.5in (826mm)
Fuel capacity (approx.):
3gal (1963-1965)/ 2-1/2gal (1966-1967)

“It is a riddle wrapped in a mystery inside an enigma.” Although Sir Winston Churchill wasn’t talking about the specifications of the Triumph T120 TT Special when he made that famous comment, he could have been.

Soon to become the prime minister of England, Churchill was referring to the role Russia might play in the Second World War when he made that statement in 1939. But his quote rings true, especially in regards to the Triumph T120 TT Specials; some of the finer points are complex and rather puzzling. Although many have written about the Triumph T120 TT Special, there are still some mysteries surrounding the line’s exact specifications — and we’ll get into that in short order.

Introduced in 1963 and running until 1967, the Triumph TT Special was built solely for the American market, where just about every manufacturer was selling seriously competitive sports motorcycles. The TT Special had definite appeal to riders interested in going fast in offroad events such as TT racing. In that style of competition, the rules of AMA flat track racing dictated at least one right hand turn and a jump, with a dirt course that could be any length.

Bill’s first TT Special

Before we go any further, we need to catch up with Bill Sherman, a farmer living near Peru, Illinois. Regular readers might recall our story in the November/December 2015 issue of Motorcycle Classics about Bill’s reunion with his old Harley-Davidson XLRTT racer.

An avid speed enthusiast, in 1963 Bill started drag, dirt track and scramble racing aboard a 1963 Triumph TR6 — the first year of the unit construction 650cc engine. TR6s came with a single carburetor, but Bill tweaked his TR6 with a twin carb Bonneville head and a few other modifications. He was fast, but he wanted to go faster.

That’s when he traded the TR6 on the 1965 Harley-Davidson XLRTT at Pierce Harley-Davidson in Dekalb, Illinois, a family-owned shop headed by namesake Wayne Pierce that also sold Triumph motorcycles. The XLRTT helped make Bill one of the fastest competitors on the drag strip, but in the summer of 1966 he bought a brand-new Triumph T120 TT Special from Pierce to compete in flat track, TT and TT scramble races.

“That bike, off the showroom floor, was about as hot as the ’63 TR6 I’d heavily modified for racing,” Bill explains. “What really got me going on the TT Special was seeing Eddie Mulder at a Peoria TT race. He dominated the 25-lap feature on that Triumph, and even though his bike would have been somewhat modified from stock, with different cams and other changes, those Triumphs were what I called ‘out of the box’ racers. I can’t remember what I had for breakfast today, but watching Mulder on the Triumph that day more than 50 years ago at Peoria stands out in my memory.”

Bill raced his 1966 TT Special for a few years, but by 1972 the bike was gone and he was dedicated to operating the farm. “About a dozen years ago, though, I thought I’d like to get a TT Special just to play around in the dirt,” Bill says, adding, “The first one I bought was a 1966 model — it’s not my original one, I would have taken any year; it’s just the way it happened. The ’66 is absolutely pristine, so I was still looking for one to ride. That’s when I found the ’67 in Florida, and then I located a ’64 at a Mid-America auction in Las Vegas.”

Learning from the expert

Jim Hiddleston of Mister Jim Motoren in Castricum, North Holland, Netherlands, restored the 1964 TT Special. With some 37 years of Triumph restoration under his belt, Jim is a noted marque expert and more than a little obsessive about Triumphs. “Through the years I have also listened to every old-timer, bought every book, magazine tear out and sales folder I could find,” he says. “I am blessed with an almost photographic memory and an obsession for detail. My only goal is to try and build them as well as the Triumph factory and as detail correct as possible. That also includes documenting them.”

Since Bill purchased the ’64, he and Jim have become good friends. And it was then, with three TT Specials to his name, that Bill realized he was more than halfway to owning all five years of production of the TT Special. He asked Jim to help him track down the remaining two machines to complete the collection, and Jim offered him a lead on a ’65 that came out of California. The 1963 TT Special in Bill’s possession was purchased directly from Jim, and it arrived on the farm in early 2016.

Ok, so now we can talk about specifications and development of the TT Special, but not without first introducing two of the big Triumph players in North America, starting in 1938 with Johnson Motors (JoMo) on the West Coast and in 1950 The Triumph Corporation (TriCor) in Maryland on the East Coast. America’s appetite for Triumph motorcycles was prodigious, and these two distributors ensured a steady stream of machines rolled onto the roads. But the motorcycles were increasingly being used in the dirt, and especially in California as tools to conquer the desert.

From the factory, the first offroad model appeared in 1949 as the TR5 Trophy, which was based on the Speed Twin and its 500cc parallel twin engine.

The Trophy had a high-level exhaust and the all-alloy square barrel top end from Triumph’s World War II generator engine. In 1951 the TR5 Trophy gained revised close fin alloy cylinders and head.

Then, in 1956, Triumph offered the 650cc TR6 Trophy, an off-roader equipped with the larger single-carb 649cc engine of the T110 Tiger, but updated with an aluminum head. The Trophy was in essence a street scrambler that could be ridden to work during the week, and then on the dirt on the weekend thanks to a quickly detachable Lucas headlight, high-level exhaust and moisture-proof magneto.

From the Trophy to the T120 TT

The Trophy was a best-selling machine for Triumph when, late in 1958, Triumph introduced the twin-carb T120 Bonneville as their fastest road-going model for 1959. Looking anything but racy with its valanced fenders and old-school headlight nacelle, the Bonneville didn’t immediately catch fire; that happened in 1960 when Triumph pared the motorcycle back and streamlined its design. This included an all-road Bonneville with high-level exhaust pipes, bash plate and Dunlop Trials tires that sold under the model code TR7/B.

“During the late 1950s and early 1960s, desert racing and other offroad events were getting to be a big deal on the West Coast,” Bill explains, “and riders and dealers alike were taking a TR6 or a Bonneville and stripping them down, removing parts such as the lights and speedometers to make desert racers out of the machines.”

And that led to the creation of the Triumph T120 TT. According to Jim Hiddleston, “[In 1962] it would appear that there had been some pre-production conference between Triumph and the various worldwide distributors as there were several new variants of the T120 straight from the start. At the behest of the two American distributors a new range was created, with the T120R Bonneville Roadster and the T120C West Coast, which was to be the first purpose-built TT bike that Triumph produced,” Jim says.

The first TT Special was built by special order for JoMo in December 1962 and featured Triumph’s latest unit-construction engine/transmission, now standard across the 650cc range of machines including the Thunderbird, Trophy and Bonneville models. The new engine used wider timing gears for quieter running, a smoother clutch, a nine-stud cylinder head, and rocker boxes with fins instead of the plain boxes found on the earlier pre-unit engines.

A JoMo brochure for 1963 listed the TT Special, excitedly describing it as “Stripped for action for experts only! The all-new Bonneville ‘TT’ Special is fitted with special 12:1 compression pistons, oversized dual carburetors, AC magneto (no battery), and racing tires — specially designed for use in professional and non-professional competition by expert riders.”

That compression ratio figure is where the discrepancies start. “The T120C (TT) model was supplied with special high compression pistons, with conflicting information listed in the build books and dispatch lists,” Jim says. “In 1963, it’s claimed 12:1 under part number CP160, but all the Triumph/Hepolite high-comp pistons I have ever seen look the same, so possibly the heads were decked to up the compression.”

Later compression ratios were 11.2:1/CP201 in 1964; 11.1:1/CP202 in 1965; 11:1/CP202 in 1966; and 11:1 with the part number revised to E6867 in 1967. “The truth [about compression ratios]? Who knows? But it looks like they weaned off on the compression as development continued,” Jim says. Further complicating matters, Triumph enthusiast Charles Rising asserts on his website that there never was an 11.2:1 compression version, a specification he puts down to a misprint in a Triumph parts supplement. Rising says there was always only the first 12:1 and the following 11:1 versions.

And that leads to another discrepancy — in 1963 Triumph didn’t stamp the crankcase with a “C” as in T120C. “If you see a 1963 Triumph that’s purported to be a TT and it’s got a C on the case after the T120, that’s a fictitious machine, and someone has re-stamped the case — they were called a C on paper but it wasn’t stamped on the engine or the frame,” Bill explains. “That began in 1964, with a C stamp. Furthermore, halfway through 1966, until the end of production in 1967, Triumph dropped the C and stamped them TT. For example, the early ’66 I have now is stamped T120C, and the ’67 is stamped T120TT.”

Further discrepancies about the T120 TT show up when production numbers enter the equation. “I’ve heard several different suggestions about how many of these bikes were built,” Bill says. “The 1963 model is rarer than the others, of course, but some sources say only seven were built, while others say 30 or 40, and I’ve also heard as many as 300 left Triumph. That’s quite a range, and getting it all straightened out is not that simple to do.” According to Rising’s website, 315 T120 TT Specials were built in 1963.

Model changes

There were, of course, a few changes across the range between 1963 and 1967, including the fenders; the ’63 in white came with painted alloy front and steel rear fenders. The machine was equipped with a pair of distinctive high exhaust pipes, one on each side of the bike.

In 1964, new forks were fitted, a magnetic tachometer went on top, and polished aluminum fenders were used. The tank was painted gold, with Alaskan White on the bottom. For 1965, Triumph changed the exhaust pipes to larger 1-3/4-inch-diameter tubes and tucked them under the engine to exit in front of the rear wheel. There were new folding foot pegs and the paint was Pacific Blue with a silver bottom. Changes in 1966 to the engine included a new crankshaft and bearings, longer kickstart lever and different valve springs. The frame was de-raked from 65 degrees to 62 degrees and the swingarm was wider. A new, smaller, 2-1/2-gallon gas tank in Alaskan White with Grenadier Red was finished off with new Triumph badges. Says Jim, “That tank design probably sold more Triumphs than any other modification they ever made!”

As already noted, mid-year through 1966 Triumph began stamping engines and frames with the TT designation and dropped the C. The final year for the model was 1967, and the engine had stronger connecting rods while stainless steel fenders now covered the wheels. On some of the last ’67s, Amal Concentric carburetors replaced the Monobloc carbs previously used. Early ’67s were finished Aubergine with gold on the bottom of the tank, while later models had a white bottom.

When Bill was racing his 1966 TT Special, he says he was 6 feet 2 inches tall and weighed 160 pounds soaking wet. Given his size — tall but light — he thinks the TT Special was an exceptional machine.

“That bike handled so well completely stock,” Bill says. “Out on the pavement just messing around, you could go through the twisties power sliding the rear. In the dirt, you never felt like you were fighting it, you were always in control. It was comfortable and usually very predictable.” Bill doesn’t know what happened to his original 1966 Triumph, but if anyone has T120TT DU39586 in their collection, he’d be delighted to hear about it. And so would we.

Although exact details regarding the Triumph T120 TT Specials might be something of an enigma, there’s no denying this one fact: The machines are very good looking and in the right hands — such as Eddie Mulder with his numerous TT victories for Triumph throughout the 1960s — very purposeful. MC

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