Cradling the new engine is a revised chassis with new geometry, which has been developed to inspire smoother handling characteristics.
This is combined with a more rigid aluminium swingarm, complete with a wider pivot, housing a fatter 140mm Michelin Pilot Street rear tyre and rim, which replaces the outgoing 130-section design. The bike feels planted and predictable at all speeds, allowing you to tip into corners with confidence and apply throttle on exit with no movement from the rear.
We also had the opportunity to test the YZF-R125 around the tight Ribera Circuit. Used by locals for pit bikes and go-karts, the dinky Yam felt perfectly geared for the short track, with plenty of tight and fast bends to achieve maximum lean, only helped by ample ground clearance.
The Michelin tyres didn’t once break traction and the confidence inspiring front end allowed you to stuff it into every apex whilst chasing the hallowed scrape of slider of tarmac. The bike also felt stable through fast changes of direction, helped by the fatter rear tyre and stiffened chassis parts.
Despite the sporty stance and slightly forward riding position, the bike remains comfortable on longer journeys and provides plenty of leg room. What’s more, the well-damped, non-adjustable suspension soaks up the majority of bumps in the road with ease, while remaining stiff enough to feel planted in the turns.
The bike gains a new engine for 2019, complete with Variable Valve Actuation (VVA). The system consists of low-lift and high-lift cams, which work on separate rocker arms. At lower RPMs, the low-lift cams will operate the valves, with the valve timing then switching at 7400rpm.
The aim of this is to achieve better acceleration, a higher top speed and a more torquey feel from the engine. As a result, there’s more bottom-end and power delivery is strong and consistent from the middle of the rev range, with the motor pulling all the way to 11,000rpm. The shift in timing is seamless, and allows you to be lazier with gear changes when you’re not in a hurry.
Exploring the VVA system
It’s a tough time for kids these days. As if the stress of ten thousand exams wasn’t enough, they don’t even get the pleasures of eye-popping two-strokes. In fact, all A1-learner legal motorcycles are restricted to around 14.5bhp (11 kW) with a power-to-weight ratio of not more than 0.1 kW per kg and a max of 125cc.
Luckily, the requirements do not specify a maximum torque, so if you are looking for an advantage in this highly competitive segment, this is the area to exploit. Which is exactly what Yamaha have done with the 2019 YZF-R125 and its Variable Valve Actuation (VVA).
Within the head is a single camshaft that operates two intake and two exhaust valves via two independent rocker arms. Shaped like a ‘Y’, these rockers are activated by the cam’s lobe and push directly on the valves to open them before they are shut again by the valve springs. Then when the revs hit 7400rpm the VVA system is activated and the magic happens.
Alongside the intake rocker arm sits another arm that is moved by the cam’s second intake lobe. Shorter than the main rocker, this arm follows the cam but does not act on the valves at low rpm.
When 7400rpm is reached and the VVA is triggered, a solenoid pushes a metal pin through the main rocker arm, connecting it to this secondary rocker arm. Thanks to the more aggressive profile of the second cam lobe, this rocker then takes over the control of the valves' movement because it is moved by the cam’s lobe before the primary rocker arm is, effectively changing the YZF-R125's intake valve timing.
When the revs drop below 7400rpm the pin is retracted and the rockers move independently again. So why is this important?
"At low revs the cam profile has a low lift, which gives less of what is called 'valve overlap,'" says Leon Oosterhof, Product Management for Yamaha Motor Europe.
"Valve overlap is the period both the exhaust and intake valves are open at the same time. Less overlap gives good low and midrange torque as well as better fuel economy. More valve overlap created by a high-lift cam delivers improved performance at high revs.
"With VVA we have given the YZF-R125 both high and low-lift cam profiles, significantly increasing its torque throughout the low and midrange without sacrificing top-end performance."
According to Yamaha the VVA system is simple tech that is reliable, effective and, for a 125, an efficient and low-cost way of boosting its low-down torque while retaining its top end.
Although it’s much too early to talk about the reliability of the new European-built machine, MCN reader reviews of previous models indicate largely positive feedback. As with any 125, if you’re buying one used be sure to check for crash damage and signs of neglect as many of these bikes will have been owned by new riders.
Although gaining no additional cost over the outgoing 2018 bike - despite a new engine and styling - the Yamaha is priced towards the premium end of the sports 125 class. At £4499, the bike is a whole £400 more than the Suzuki GSX-R125, £100 more than the standard Kawasaki Ninja 125 and £50 more than the KTM RC125.
What’s more, remaining Honda CBR125Rs found in the dealer network are a whole £500 less, too. That said, it is £200 cheaper than Aprilia’s premium RS125.
Unlike some of the less expensive options, the R125 exudes quality and will stand out as the poster bike for many budding biking teens, thanks to the quality components and styling mimicking more powerful sports machines in Yamaha’s range. What’s more, it also offers some of the best engine and braking performance in this class, as well as an impressive claimed fuel economy.
Rival 2019 prices:
- Suzuki GSX-R125 = £4099
- Kawasaki Ninja 125 = £4399 base, £4499 for KRT version
- KTM RC125 = £4449
- Honda CBR125R = £3999 (discontinued)
- Aprilia RS125 = £4699
Yamaha have developed a number of new optional extras for 2019, ranging from larger screens, to a rear seat cowl. Prices range from £57 for a set of LED arrow indicators, to £700 for a full titanium Akrapovic exhaust.
The £700 pipe is expensive and makes little to no difference in performance or noise, thanks to a fused baffle courtesy of Euro4. As of March, Yamaha will also sell you a Sports Kit consisting of a larger 'Endurance' screen, number plate bracket, side-mounted crash protection and LED indicators.
Another welcome addition to the bike is the inclusion of a new LCD display, replacing the previous bikes’ convoluted three-part unit, which could be hard to read on the move. In its place comes a much cleaner, more logical device, housing all of the features you would come to expect for a modern machine, alongside a VVA actuation indicator and a personalised welcome message when the key is turned, which can be altered to display your own name.