About Triumph's Single Cylinder TR-Series Motorcycle Engine

It's always exciting when a major motorcycle manufacturer releases a new engine. It's the beating heart of the machine and the most important factor in matters of performance. The most innovative engines are often used in several models and across multiple generations, so it's worth looking into what kinds of changes the company has made. Engine innovation isn't just about raw power, though. Efficiency, reliability, and form factor are sometimes overlooked in favor of horsepower and torque, but these variables are no less important. They make it so that even smaller bikes can boast excellent performance. Triumph has just announced a new motor that appears to be a paragon of these virtues.

Triumph is launching a brand-new 400cc single-cylinder engine that will be installed in two of the upcoming models being released by the UK-based brand: The Triumph TR Series Speed 400 and the Triumph TR Series Scrambler 400 X. This is exciting news for fans of the brand–especially those who might be looking for a good bike to be their first ride. Before you head to your local dealership, however, you might be interested in learning a bit more about these motorcycles and the new engine that's going to make them run.

Triumph's new liquid-cooled, single-cylinder engine seems to boast a fair amount of power in a small package. It probably won't be competing with its larger V-twin siblings in a drag race any time soon, but that doesn't mean that it doesn't pack its fair share of get-up-and-go. Triumph states in its product description, "The fuel-injected, 398cc single-cylinder engine combines Triumph's trademark modern classic style with state-of-the-art engineering to deliver a class-beating 39 HP of power and 28 lb-ft of peak torque with an evocative, rich, and distinctive exhaust note from the twin-pipe silencer." It has an 89.0 bore, a 64.0 stroke, and a 12:1 compression ratio. It also utilizes a Bosch electronic fuel injection system with electronic throttle control.

This makes it appear that Triumph's engineering team is attempting to maximize efficiency on this particular engine block. There might only be one cylinder inside the casing, but it has a four-valve, dual overhead camshaft cylinder head which is known to enhance both power production and throttle response. On top of that, Triumph claims that it has perfectly weighted and balanced the crankshaft in order to "optimize inertia." It also has a finger-follower valve train, which allows you to safely rev the engine higher to get a bit more boost from each gear as you make your way up the six-speed gearbox that the engine is paired with.

All of this adds up to what should be a fuel-efficient motor that is more than capable of powering light to mid-sized naked street bikes -– and that's just what Triumph is doing with it.

The Triumph TR Series Speed 400 is the smaller, more street-oriented, and more budget-minded bike of the two. It has the stripped-back, naked style that has become increasingly popular in street bikes. Its design simultaneously appears both classic and modern, while its narrow frame looks like it is intended for agility and easy handling. The Specs listed on Triumph's page state that the Speed 400 has a hybrid spine that has a perimeter made from tubular steel and a bolt-on rear subframe. It has 43 mm upside-down Big Piston forks for the front suspension and a gas monoshock RSU with an external reservoir for the rear. It has ABS front and rear brakes.

This is not a large motorcycle. It has a 31.1" seat height and weighs 375 lbs. on a full tank. This, combined with its relatively low MSRP, which starts at only $4,995, will likely make the bike an attractive option for new riders who are looking for an easy Triumph motorcycle to learn to ride on. This super lightweight and nimble design also means that its 398cc engine should have no trouble getting you where you need to go. On paper, the Speed 400 seems like an excellent choice for those who just need a dependable ride to get them around town.

The Scrambler line has been around since the 1950s, and the Triumph Scrambler 900 is considered one of the best motorcycles the company ever made. If the name weren't enough of a hint, all it takes is a glance, and you can probably tell that the Triumph TR Series Scrambler 400 X is designed to handle more rugged terrain. These two bikes might share the same 398cc engine and the same general shape, but it's clear from the outset that they will appeal to two very different kinds of riders.

The Scrambler 400 X MSRPs at $5,595, making it the more expensive option of the two. It has a similar Chassis to the Speed 400, though the tires are a bit bigger and there's a touch more wheel travel in the suspensions. Its frame, swingarm, and wheels are made from the same materials, though they are calibrated a bit differently to approximate for the changes in wheel size. Even the exhausts, which look quite different from the outside, are both actually stainless twin-skin header systems with stainless-steel silencers. Other than the larger, treadier tires, the main difference between the two seems to be that the seat is a smidge higher at 32.47", and it weighs a bit more at 395 lbs.

These design modifications might seem subtle, but they add up to a bike that is much more comfortable going off-road. So while city riders might prefer the Speed 400, those who like to take their ride down the occasional dirt road will probably be better off with the Scrambler 400 X.