1970 Triumph Daytona

[DaveM]

1970 Triumph Daytona 500​

1970 TRIUMPH DAYTONA – WHAT’S IN A NAME?
Triumph derived the name of this bike from Buddy Elmore’s win at the 1966 Daytona 200 at Daytona Beach FL riding a Triumph T100T Tiger 500 twin. It was Triumph’s first-ever Daytona victory, with an average speed of 96.6 mph. By 1967, it was an official production model with the designation T100R Daytona 500. Just to kick things off, Gary Nixon won the 1967 Daytona 200 on a new Triumph Daytona.

1970 TRIUMPH DAYTONA 500 BACKGROUND
Triumph master engineer Doug Hele completely reworked the cylinder head for the Daytona race bike such that 2 Amal carburetors were used (instead of the usual one), and the valve angles were reduced by 2-degrees to alleviate clearance problems between the two valves during overlap, due to the larger intake valves. Contrary to British custom, it was also an “oversquare” engine, meaning that the bore was larger than the length of the stroke. This made it “peaky”, meaning there was very little power at low RPMs, and it wasn’t until about 3500 RPM that it started to come alive. The valvetrain tended to wear out prematurely, causing excessive oil consumption. For the 1969 Triumph Daytona, they swapped the old timing-side bush (or bushing) for a ball bearing, and installed a roller bearing on the drive-side, greatly strengthening the bottom end and prolonging engine life.

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1970 Triumph Daytona SPECIFICATIONS​

Model designation Engine type Displacement Bore & Stroke Compression ratio Fuel system Horsepower @ RPM Primary drive Clutch Gearbox Shifter Final drive Frame type Suspension, front Suspension, rear Brakes, front Brakes, rear Tire, front Tire, rear Wheelbase Curb weight Fuel capacity

T100R Air-cooled OHV vertical twin 490cc / 30 ci 69mm X 65.5mm 9.0:1 2- 26mm Amal Concentric 39hp @ 7400 rpm Chain Multi-plate, wet 4-speed constant mesh Right-foot Chain Single down tube Telescopic fork, hydraulic Swing arm w/2 coil-over shocks 8-inch TLS drum 7-inch SLS drum 3.25 X 19 4.00 X 18 53.6″ / 1360mm 386 lbs / 175 kg 3.75 US gal / 14 L

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[grandpaul]

I've owned 2 of them, and restored 3 others.

Very nice bikes, but not quite enough "oomph" in stock form for sustained highway riding at 70+

 

[Rudie]

Rubbish research.

Buddy Elmore’s win
riding a Triumph T100T

"T100T" is the designation of what Triumph called the 67-70 "UK & General Export" version of the Daytona; i.e. not used 'til after the 66 Daytona win ...

Triumph wished they could have used off the shelf 500 engines ... Many of the changes that eventually made it on to 67-on engines - bigger valves, twin carbs, roller and ball main bearings, exhaust balance pipe and crankcase breathing (all twins) - were changes made to the existing 500 engine so it would make enough power to beat a HD KR and stay together long enough to win races. The race engines also had mods that never made it on to road bikes - e.g. head bolted through the block to the crankcase. The racers also had completely different frames.

1967, it was an official production model with the designation T100R Daytona 500.

67, it was called "Tiger Daytona" - the cast "Tiger" sidepanel badge was still fitted.

Gary Nixon won the 1967 Daytona 200 on a new Triumph Daytona.

Again, Triumph wished; he won on a developed version of the 66 racer. Not mentioned so often is Triumph tried for the hat-trick in 68 but ... did not succeed.

Anyone really interested should find a copy of Claudio Sintich's Road Racing History of the Triumph 500 Unit Twin.

Contrary to British custom, it was also an “oversquare” engine, meaning that the bore was larger than the length of the stroke. This made it “peaky”, meaning there was very little power at low RPMs,

The unit 500 was always “oversquare”, from the first in 1959. It could be considered “peaky” ... if you have only ever ridden British 650 and 750 twins. Otoh, if your experience is only a little wider, no.

Pity they could not be bothered to find pictures of a standard "1970 Triumph Daytona 500" ...

Fuel capacity
3.75 US gal / 14 L

That is the larger "UK & General Export" tank, US 500 tanks were/are always about a gallon smaller ... from about 61 onwards,

 

[speedrattle]

my first motorcycle was a 1962, registered as a trophy 500. it would only go 80 mph.

don't have any photographs, and i've always wondered just what kind of a bitsa it was. i rode it it around kuala lumpur, and the possibilities of its provenance there are infinite.

 

[tobyb]

The main changes to the Unit 500's was after Daytona in 1967, the factory machines while fast, where 'blowing up' . Where as the machines that where being raced by Tri-Cor where recording the same times and stating together. So Burt Hopwood went over to the Tri-Cor camp to see what was going on. That's when he found out that the Tri-Cor machines had been modified to take a roller bearing in place of the bush on the timing side. After a bit of negotiation Burt was able to borrow a a couple of the Tri-Cor engines and subsequently the factory machines 'cleaned-up'. From 68 on this modification along with a few other where incorporated in the 500 range. The other main upgrade was in 1974 when the Daytona's the only road based 500 in the range was fitted with the front forks and disc brake taken from the T140. I have owned 3 of the 'late' 500 machines including a 1974 and have found them to be of a 'rider' machine then the bigger twins and not much slower.

 

[John Bakker]

Here's a photo of a 1970 Daytona I used to own.

 

[3 TriumphT100R]

Thanks to all that provided that background on these great bikes. I am currently working on a recent purchase of a 1973 Daytona. One item I am unclear on is the equalized exhaust. I read somewhere once that it was to comply with noise laws in the U.K. and had nothing to do with performance. I always wondered about that. Back in the mid 60's when going to the Honda shop with my 160, my eyes began to wander over to the "real" bikes as the dealer also sold Triumphs. The Daytona was the 1st "real" bike I ever wanted but never had until the aforementioned Daytona. I have had a lot of bikes over the years and know I will enjoy this one a lot. Still have a Norton and a T140 but I still think these 500's are great fun to ride.

 

[Rudie]

1973 Daytona
equalized exhaust. I read somewhere once that it was to comply with noise laws in the U.K. and had nothing to do with performance.

By "equalized exhaust", you mean the balance pipe, between the exhaust pipes close to the cylinder head? If so, fitted from the 69 model year, when there were not any noise laws anywhere. Triumph found there was slight reduction in noise from the exhaust.

Your bike has "push in pipes" - exhaust pipes that simply push into the ports in the cylinder head, rather than pushing over steel spigots screwed into the head? If "push in", balance pipe was standard, you might find it helps keep the main pipes ends in the ports ...

 

[3 TriumphT100R]

By "equalized exhaust", you mean the balance pipe, between the exhaust pipes close to the cylinder head? If so, fitted from the 69 model year, when there were not any noise laws anywhere. Triumph found there was slight reduction in noise from the exhaust.

Your bike has "push in pipes" - exhaust pipes that simply push into the ports in the cylinder head, rather than pushing over steel spigots screwed into the head? If "push in", balance pipe was standard, you might find it helps keep the main pipes ends in the ports ...

proof positive once again you can't believe everything you read I guess. I always thought it must be performance as my '57 Chevy had more power from the headers I put on it.