Aprilia RS4 125 (50) (2011-current): Teenagers' dreams

     Engine: The single cylinder six-speed 125 c.c. engine delivers 14.8 bhp/10500 rpm and 1.1 Kgm/8250 rpm, claimed figures.
     A minimum of …5000 rpm will be required on the road to obtain adequate thrust. Below that figure, engine is almost like an athlete …sleeping. At 7000 rpm that man is up, washed and shaved! At 8000 rpm he is virtually running, an observable power and sound step is noticed, up to 11200 rpm where the rev limiter intervenes.
     To get decent acceleration, within the limits of the restricted power provided of course, the clutch abuse is required.
     The engine feels like a tuned yet small capacity one. The speed of 100 Km/h is achieved fairly fast, the bike will preserve such a speed easily. The silencer is mounted under the fairing.
     Riding position: The height of the saddle is relatively low, 820 mm. The width of the saddle is narrow at the front, low stature riders will not face any problem. The dimensions of the bike are normal, they do not refer to a small 125 c.c. motorcycle. The fairing at the very front is the only part of the bike which could be considered to be wide.
     The bike feels light, 135 Kg nominal dry. Rider is placed mostly over the bike. Riding position is purely sporty, not a racing one though. The torso of the rider is leaning forward, riderĘs arms get some of the weight, riderĘs feet are placed backwards.
     On the road: An aluminium perimeter frame is equipped. Suspensions feel soft, the rebound damping of the fork is slightly softer than ideal. An inverted 41 mm fork is equipped, the swing arm is asymmetric. There isnĘt any linkage for the shock, suspensions are not adjustable.
     OE tyres are Savva MC 25 Bogart with dimensions 100/80-17 at the front and 130/70-17 at the rear. They are considered to be an inferior choice for this bike. They will require decent roads and up to a nimble pace of riding in order not to impose severe riding restrictions.
     In town the little RS4 is striving to prove that itĘs a sports bike also. Except from the small engine capacity, hence the weak performance, it feels like a big bike in town. Its neutral, it will be great for any rider dreaming about commuting on an urban superbike. However restrictions will be asked. The weight on riderĘs hands will be felt.
     Steering lock is the same with that of the big bikes. Its not a problem for the rider, however he will be wondering why didnĘt Aprilia resolve this issue at a 125 c.c. bike.
     Filtering is good, despite that the height of the bikeĘs mirrors is the same with that of car mirrors.
     Street imperfections are absorbed relatively well, rider could perceive such a comfort as an example of increased feedback. Generally speaking the RS4 is a comfortable little bike, rider will not be puzzled.
     On B-roads, stability is the key riding feature. Agility is considered to be a …theoretical riding element, despite the small, 1350 mm wheelbase. Thus once more, despite engine performance, riding refers to a larger motorcycle.
     At the fast pace the tyres fitted will definitely impose restrictions on low friction factor B-roads. Rider will not feel confident to charge. ItĘs a pity to moderate the cornering potential of such a bike due to the cost of production. Fortunately for the rider, this problem can be resolved easily.
     On high friction factor B-roads, the RS4 is very stable and neutral. The small engine will make things interesting only on downhill roads, due to the moderate performance. The RS4 will ask for some additional front end weight transfer as well as some additional feedback from the tyres.
     If these three requirements are met, rider will be overwhelmed, that is to say for the standards of the category. Riding confidence is superb. On such conditions the RS4 is a great riding teaching tool for novice riders, it will forgive many mistakes.
     On the highway the RS4 provides great confidence and stability. This will soon expose the natural weakness of the 125 c.c. engine though. The 122 Km/h mark is the most that the rider will get at the top, indicated figure.
     Generally speaking this kind of abuse is not recommended, that is the highway use of course. The robustness of the bike will make things very easy on the highway for the rider, the speed of 100-120 Km/h will be comfortable, despite the screaming engine. Air protection will not result in a problem for the rider at such a speed.
     A 300 mm disc brake, four pistons calliper are equipped at the front, a 220 mm disc brake, single piston calliper are equipped at the rear. Steel braided lines are installed at both ends. Braking is powerful, initial bite is moderate, feedback to the rider is relatively good. In other words brakes are user friendly, they will be also satisfying to fast riders. In case of stickier tyres mounted on the bike, braking feedback should get improved.
     Model history/reliability/quality build: The Aprilia RS 125 was introduced in 1993, which was a pure sports, two stroke bike. Quality build was superb then, real power output was 26-30 bhp, depending on the year of manufacture. Indicatively, the top speed of that bike was 150 Km/h.
     The RS4 was introduced in 2011, many parts are derived from the cousin model Derbi GPR. The actual power produced is roughly half of that by RS125, the lower production cost target is also evident. The two stroke  RS 125 is also produced.
     The 50 c.c. engine is still a two-stroke one, delivering 2.7 bhp / 5250 rpm and 3.6 Nm / 4000 rpm torque, quite low figures indeed.
     Comments: A minor storage space is provided under the seat. A LED tail light is equipped. Between the fairing and the small engine there is a great gap, the spacers shown at the photos are intended for such a use.
     Stray cables can be seen powering the front lights, indicators etc. which provide a must-take-them-out-now-for-track-use hint to the rider. The mirrors of the bike from one point of view resemble to an insect antennas (!), which also provide this sort of track use hint.
     The list of optional equipment includes quick shifter, a pillion seat cover etc.. The shifter permits the rider to up-shift a speed without quitting from the throttle or engaging the clutch. Three color options are there for the customer. White, black and the SBK replica which is the bike tested here.
     The design similarities are evident with the ApriliaĘs flagship RSV4, which looks almost the same with that of the World Champion Max Biaggi. Except from the outline, the face and the colors, there are some exciting details such as the tail and the edges on the tank and the fairing. The No1 graphics on the tail, the fuel tank and the face and the Max Biaggi stickers do look cool. The upper triple clamp is also nice.
     These design similarities could deceive people not familiar with motorcycles from some distance, thinking that this is the RSV4, although the threatening sound of the big brother and the tiny rear tyre of the RS4, will soon reveal the truth.
     The frame, fork and the beautiful swing arm look quite robust, they can cope with greater engine power. Of course the firmness of the bike was not questioned during the bike test. In terms of riding the naturally low power output of a four stroke 125 c.c. engine and the OE tyres are the major reasons which will tame great riding expectations. As an example, a runner would not compete wearing plain All Stars snickers, even if he were a champion! Fortunately a tyre change will restraint the rider from searching only for top class roads to practice cornering.
     Learner riders above 16 years of age for most of the European countries, are the target group for Aprilia, the RS4 surely looks like a dream bike to teenagers. If these riders plan to practice some track days in order to become faster avoiding the on-road risks, the RS4 becomes a superb choice.
     Consequently due to the superb riding potential and the exotic design which is copied from the 1000 c.c. sisters, the RS4 is an integrated and proven bike which will attract many teenagers.

Price 125 c.c.: 4170 §

Price 50 c.c.: 3680 §

+ Design

+ Riding teaching tool for novice riders

- OE tyres

- A legal, larger engine capacity version please… 

More, specifications

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