Triumph Street Triple. September 2007
The 675 engine delivers 108PS and 69Nm of torque, for strong low and mid range performance.
Design and Development The Street Triple project started in earnest back in November 2005 when the Daytona 675 was close to completion. The objective was clear: to create a truly sexy naked sports bike, accessible to new riders reluctant to take on the bulk and weight of a 1,000cc bike, yet exciting enough to be rewarding for those with plenty of riding experience.
The first prototype of the Street Triple was tested by Triumph's development riders in Spain in December 2005.
Engine
The Triumph Street Triple shares the same 675cc, water-cooled three-cylinder, 12-valve engine as the Daytona 675 but with a slightly different cam profile, giving more low end torque and a lower rev limit of 12,650 revs. The engine offers a broad spread of power, with strong bottom end torque, backed by a heavy mid-range punch and topped with a searing burst of peak power, all with that characteristic three- cylinder roar. The harmonic tone of the exhaust has been perfected by modifying the lengths and expansion ratios of the manifold and silencer to change the acoustic loading on the system. Concentrating on idle, hard accelerations and overrun to generate and tune the characteristic triple sound, the resulting howl is as distinctive and spine-tingling as ever.
The close ratio six-speed gearbox maximises the effectiveness of the engine's impressive power and torque, meaning you've always got the perfect gear. Peak power of 108PS (106bhp), delivered at 11,700rpm, places the Street Triple at the top of the middleweight naked category and with 69Nm (51ft.lbf) of torque at 9,100rpm the bike is guaranteed to out-perform all of its competitors. But the best thing about the bike's performance is that you don't have to work hard to get it: the Street Triple produces more than 60Nm (44ft.lbf) of torque from 3,500rpm right through to 12,300rpm.
Included valve angle is 23, leading to a nicely compact and efficient combustion chamber. Inlet valve diameter is 30.5mm, exhaust 25.5mm and single springs are used for both the inlet and exhaust valves for durability at higher rpm. The exhaust valves themselves feature a 4mm stem and are made from a Nimonic (nickel-based) material allowing them to run hotter. Combustion chambers and inlet port throats are fully CNC machined for greater accuracy and precise gas flow control. The 675 engine has been refined without detracting from the triple's innate character and while the Street Triple can perform like a racing thoroughbred, Triumph's typical toughness is engineered into every part. The 675 engine is designed to be pushed hard, over and over again. The engine is very much a part of the styling of the bike and the aesthetics have been carefully considered. The combined oil and water pump are neatly packaged within the engine to remove unsightly pipe work.
The Street Triple's sophisticated Keihin closed-loop fuel-injection system uses three 44mm diameter throttle bodies, with three multi-spray injectors mounted in the throttle bodies. The bike carries sensors for throttle position, crank position, gear selected, road speed, air pressure, air and coolant temperature, plus a tilt sensor to stop the engine if the bike is dropped. Fresh air is drawn through a duct in the front sub frame below the headlights and passes directly through the headstock to the airbox. The engine control unit (ECU) also controls engine idle speed and the operation of the secondary Triumph Street Triple
Engine: Liquid cooled, DOHC, in-line 3-cylinder
Bore & stroke: 74 x 52mm
Capacity: 675cc
Compression ratio: 12.65:1
Fuel System: Multi-point sequential electronic fuel injection with forced air induction and SAI
Exhaust: Full stainless streel 3 into 1 into 2 exhaust system with twin high level silencers
Ignition: Digital inductive type via electronic engine management system
Max. Power: 108PS @ 11,700rpm
Max. Torque: 69Nm @ 9100rpm
Transmission: 6 speed, close ratio
Frame: Aluminium beam twin spar
Swingarm: Braced, twin-sided, aluminium alloy
Suspension front: Kayaba, 41mm upside down forks. 120mm travel
Suspension rear: Kayaba, Monoshock. 126mm rear wheel travel
Brakes front: Twin 308mm floating discs. Nissan 2 piston sliding calipers
Rear: Single 220mm disc. Nissan single piston caliper
Overall length: 2030mm
Overall width: 736mm
Overall height: 1250mm
Seat height: 800mm
Dry weight: 167kg
Wheelbase: 1395mm
Fuel tank: 17.4 litres air injection system which reduces the hydrocarbon emissions from the exhaust.
Available November for a RRP of $11,990 +ORCs.
