Posted: 10 Jan 2013
Aprilia is arguably responsible for more motorcyclists catching the sports bike bug than any other manufacturer in recent years. Its RS125 two-stroke sports learner bike was the machine to have because it was a genuine track refugee and could easily be tweaked to liberate 25bhp. The replacement for this cult machine is the environmentally friendly, power-capped RS4.
In a battlefield full of learner-legal bikes the RS4 stands out. Not just because it looks every millimetre the perfect race replica but also because it performs like one within the walls of legality.
The fuel-injected, single-cylinder, water-cooled engine delivers crisp drive from 1mph all the way to the regular 67mph top end – it can go faster downhill or with a decent length of straight road, but in the real world that’s about it. But at least the RS4 maintains this speed whereas Honda’s CBR125R and others will start to slow at the sight of an incline.
Helping to achieve top speed in decent time is an option-to-buy quick-shifter unit. A first for a road-going 125, it is lifted from an expensive track-only race kit. This simple bolt-on device cuts engine power to allow clutch-free gear shifts up the gearbox every time the gear lever is moved. With six gears to shift to keep clear of traffic it makes for a brilliant rider aid.
Aprilia knows learner riders come in all shape and sizes and have built the RS4 to accommodate the masses. There’s a lot more room behind the fairing than its overall size suggests. Of course the riding position is pure racing tuck, but it isn’t crippling and is a taster for what the chassis is capable of when the urge to attack roundabouts or A/B-roads.
Given that the suspension is non-adjustable it does a good job of relaying info from the tyres while supporting rider and chassis weight – 15-stone-plus riders will reduce this effect by taking up most of the rear shock’s travel. Add to the mix a 300mm front disc with four-piston caliper, tyre sizes that still grace bigger capacity bikes and a stiff aluminium chassis, it’s therefore understandable why RS4 production racing is gaining popularity in mainland Europe.
As a learner legal bike the RS4 is without doubt an expensive introduction to motorcycling. But the point is it is a genuinely scaled down version of Aprilia’s big-cubed sports machines – aluminium frame and curved swingarm are not cheap to produce, even when they are also used on the Derbi GPR125.
+ points – best looking learner machine available. Gives a truthful account of what sports bike riding is about.
- points – price. It’s also a shame Aprilia doesn’t produce an off-the-shelf 250/350cc engine to fit in for the next step to gain a full licence.
Power: 14.7bhp, n/a-ft lbs
Dry weight: 134kg
Seat height: 820mm
Colours: White, black, optional WSBK replica