Triumph Daytona
Triumph Daytona Background & History
The Triumph Daytona was a street-legal race bike. It was introduced as a 1967 model after American racer Buddy Elmore won the 1966 Daytona 200 on a ‘works special’ 500cc Triumph Tiger 100, with an average speed of 96.8 mph. Triumph named the bike after this win and produced the 500cc Daytona from 1967 through 1974. It has also been known as the Tiger Daytona.
In the late 1950s BSA, who ownedTriumph, was obsessed with unit-construction. Virtually every bike on the market in those days was of non-unit construction. This means that the engine, the primary chain case and the gear box were all separate units that were held together by a set of brackets. Unit construction coupled all those components into one unitized casing, hence the name. The first of BSA's and Triumph's bikes to go through it were Triumph's 350 twins in 1957. Then in 1959 Triumph and BSA converted over their 500 twins and finally in 1963 their 650s. The unit construction 500cc Triumph engine benefitted greatly from the process. The unit construction engines were stronger, lighter and more powerful than before, and they took well to modifications (ie: hop ups). That was good because the Triumph Daytona was a beast!
1968 Triumph Daytona 500. Not the SLS front brake, replaced with a TLS later in 1968.
Triumph Daytona Engine Design
The new unit-construction 500cc Triumph twin shared engine architecture with Triumph’s 350 twin. However, the unit-construction 500 twin is unique among Triumphs in that it’s an oversquare engine. This is major, as every other Triumph, be it a single, twin or triple, is under square. This refers to the relationship between the bore and stroke of the engine. Oversquare means that the bore number exceeds the stroke number, big bore, short stroke. Undersquare means that the bore is less than the stroke, small bore, long stroke. This makes a huge difference in the performance characteristics of that engine. An oversquare engine will likely produce more horsepower, but at a higher RPM. An undersquare engine would likely produce more torque at a lower RPM. Almost all British and American motorcycles from this era were undersquare. This was standard practice in ancient times. Even car engines were almost universally undersquare until the mid-1950s. Then, suddenly it was in fashion to have an oversquare, high-compression engine. Cadillac and Oldsmobile were t he first in 1949 and everyone else followed. But that never happened within the British motorcycle industry. Almost every classic British motorcycle yoiu can think of is a small bore and a long stroke.
Not the Triumph Daytona, or any of Triumph's unit-construction 500 twins. Even at that, they weren't grossly oversquare. Square would see bore and stoke being equal. But the mildly oversquare Triumph Daytona had a bore of 69mm and a stroke of 65.5mm. When the 750cc Triumph Trident triple launched in 1969 and word got out that they'd cobbled together three 250s to make the triple, people gave the Trident the nickname "a Daytona-and-a-half". But this wasn't actually true. When designing the Trident, Bert Hopwood considered using the Triumph Daytona's hardware set, but felt it would make the engine too wide. So he opted instead for three component sets from the Triumph/BSA 250 which had a bore and stroke of 67mm X 70mm. That's a 2mm difference per cylinder or 6mm total for a triple. It doesn't seem like that would have been enough to make the decision for them, but there is is.
The Triumph T100 was tuned to make nearly the same horsepower as the 650s!
Triumph Daytona is a Screamer!
The Triumph Daytona 500 benefitted greatly from the principal of large bore, short stroke. This was one fast little motorcycle. Triumph Chief Engineer Doug Hele applied the same tuning tricks to the production Triumph Daytona that won at the Daytona International Speedway. He installed a new cylinder head with the valve angles reduced by 2 degrees, larger intake valves and twin Amal Monobloc carburetors combined to make 41 horsepower at a whopping 7,400 RPM. That’s almost what the 650s were making! The 650cc Triumph TR6 made 43 hp. The Triumph Daytona was a screamer!
1970 Triumph Daytona. Note the TLS front brake. Big improvement.
Triumph Daytona Brakes
The introductory year 1967 Triumph Daytona launched with a single leading-shoe (SLS) front brake, but in 1968 it was upgraded a twin leading-shoe (TLS) front drum for improved breaking. It’s noteworthy that the 500cc Triumph Daytona used the same 8-inch front brake as the bigger, heavier, faster 650s. This was a serious race machine. When the 650s switched over to conical brake hubs in 1971, Triumph’s 500s kept their old brakes until the end of production in 1974. The TLS front drum was actually a better-performing brake than the later conical hub-brakes. But the conical hubs looked cooler.
1971 Triumph Daytona 500.
Triumph Daytona Books
 |
More Triumph Motorcycles Pages
Hope you're enjoying my website. Glad you're here, take some time to look around. I'm just getting started though, with lots of great content, pictures and specs on literally hundreds of classic British motorcycles left to go. It is my goal to cover every year of every make, and every model of British bike. You can join me in my quest. If you have a classic Brit bike, take and/or send me some great photos of it along with a description. Email coming soon. More pages coming soon. Please be patient, and hold on to your hat. Thank you for visiting ClassicBritishMotorcycles.net.
Copyright 2024 by ClassicBritishMotorcycles.net. All rights reserved.
