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By Dave Porter, Customer and Technical Support at The Bonneville Shop
It was brought to my attention recently while updating Triumph 500 valve product descriptions in our catalog, that there should be a blog to help illustrate some of the history and evolution of the mighty Daytona Tiger 100. Bert Hopwood and Harry Sturgeon were becoming increasingly concerned in 1965 about the forthcoming Honda CB450, a double-overhead cam 450cc twin.
“Bert Hopwood and Harry Sturgeon were becoming increasingly concerned in 1965 about the forthcoming Honda CB450, a double-overhead cam 450cc twin.”
Doug Hele and the Daytona
The Triumph T100 models had always been a more than adequate performer, and even had enjoyed some racing success, with Don Burnett winning the 1962 Daytona 200 Experts race in 1962 aboard a Triumph Tiger 100, despite little to no interest from managing director Edward Turner in competition events. By 1965, Turner had relinquished control of the BSA Group (Triumph’s parent company) to Hopwood and Sturgeon.
With no time to develop a new 500cc twin to compete with the technological advances brought forth with the DOHC Honda, they summoned Doug Hele to build a competitive T100 that would be capable of winning the 1966 Daytona 200 Experts Race…with nine months to do so! The Daytona 200 was a high profile motorsports event which was dominated by the 750cc flathead Harley-Davidsons, and Cal Rayborn had already been the fastest qualifier for the 1966 race aboard his factory-tuned side-valve Harley at 134 mph, gaining the pole position in doing so.
Triumph trotted out four of Hele’s specially prepped T100s for the 1966 Daytona, to be piloted by riders from Johnson Motors (JoMo) and Triumph Corporation (Tri-Cor). Buddy Elmore won the race despite starting way back in the field, due to a slower qualifying speed caused by an oil pressure issue. Elmore and Gary Nixon diced back and forth until Nixon suffered a deflated rear tire. Despite the time spent in the pit dealing with the tire repair, Nixon still managed a ninth-place finish.
It was from this monumental race that the legend of the Daytona Tiger 100 was born. Triumph was to repeat with a 1-2 finish at Daytona for 1967, with Gary Nixon finishing ahead of Buddy Elmore as the victor. Six of Doug Hele’s T100s finished in the first fifteen places of the 97 contestants in 1967. Needless to say, the new twin-carburetor Daytona models were selling at a brisk rate, with many of Hele’s upgrades finding their way into production over the ensuing model years.
1967 – 1969 Triumph Daytona
One notable upgrade was the change to a larger 1-17/32” head diameter on the inlet valves of the 1967 Triumph Daytona model. To accommodate this, some changes were made to the cylinder head, including the elimination of the “squish-band”, a transitional chamfer around the edge of the combustion chamber. The result was a true hemispherical combustion chamber which allowed the use of the larger inlet valves and the new high-compression pistons with elevated domes.
For 1968, a revised single carburetor intake manifold with the same bolt pattern as the twin carburetor manifolds debuted, along with 5/16-18 TPI UNC mounting studs. Many of Hele’s racing modifications were implemented by 1969 on the standard production T100R models, including improved valve angles, which improved the fuel charge flow.
While there is some interchangeability between the 1968-later cylinder heads, care must be taken to closely observe pushrod tube specification and the associated seals, as well as the depth of the port for the top of the pushrod tube. This has long been a source of confusion, so it is best to measure the gap between the cylinder barrel and the cylinder head with the head gasket fitted, top end assembled and lightly snugged down, just enough to seat the pushrod tubes and seals.
Triumph Service Bulletin #324 goes into detail regarding the configuration and procedure required to achieve the desired .030”-.040” clearance between the head and the head gasket. I have seen it suggested before that the pushrod tube seal specifications for the 1973-1974 TR5T models are the best bet for sealing the 1969 and later T100 cylinder heads, which include the 71-2576 pushrod tubes, (4) 71-1283 O-rings, (2) 70-3547 seals, and (2) 71-1707 sleeves, or “wedding bands”.
The end of the Classic Triumph Daytona
The T100R Triumph Daytona models are one the most tractable and beloved Triumph models of all. The final T100R model year was 1974, of which fewer than 2000 units were produced, with production ending abruptly in September 1973 due to the Meriden workforce strike. Interest in the C-range 500cc models has been gaining momentum over the past 15 years due to the favorable availability over the pre-oil in frame 650 models, and relative affordability, thanks to today’s aftermarket.
In the early 2000s, many T100 Triumph Daytona spares were more expensive than the same parts for a 650 since they were often new-old-stock, and reproductions simply weren’t yet being manufactured in mass. We are committed to increasing our offerings of C-range spares to service this niche. Thanks for reading!
