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Aprilia RS 125R Extrema

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Make Model

Aprilia RS 125R Extrema

Year

1994 - 95

Engine

Single cylinder, two stroke, reed valves induction

Capacity

125 cc / 7.6 cu in
Bore x Stroke 54 x 54.5mm
Compression Ratio 14.5:1
Cooling System Liquid cooled

Induction

Dell'Orto VHSB 34LD

Ignition

Electronic

Starting

Electric

Max Power

24.8 kW / 34 hp  @ 11000 rpm

Max Torque

25 Nm / 2.5 kgf-m / 18.4 lb-ft @ 9000 rpm

Transmission

6 Speed

Final Drive

Chain

Front Suspension

Upside-down forks, Ø 40mm

Front Wheel Travel

120 mm / 4.7 in

Rear Suspension

Monoshock
Rear Wheel Travel 120 mm / 4.7 in
Front Brakes Single 320 mm discs, 4 piston caliper

Rear Brakes

Single 240 mm disc, 2 piston caliper

Front Tyre

110/70-17

Rear Tyre

150/60-17

Dry Weight

115 kg / 254 lbs

Wet Weight

142 kg / 313 lbs

Fuel Capacity 

11.5 L / 3.0 US gal

Consumption Average

5.1 L/100 km / 19.5 km/l / 45.9 US mpg

Braking 60 km/h / 37 mph - 0

13.2 / 43.3 ft

Braking 100 km/h / 62 mph - 0

37.9 m / 124.3 ft

Standing ¼ Mile  

14.3 sec / 148.0 km/h / 92 mph

Top Speed

171.3 km/h / 106 mph

Road Test

Tuttomoto 1994
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Aprilia RS125R Extrema vs Cagiva Mito Race

IF YOU crave the quiet life, don't even think about an Aprilia RS125R Extrema. The easy sophistication of modern motorcycling is definitely not on the agenda here. Neither are workaday concepts such as 'trickling through town unnoticed', 'just riding round a bit' and 'being remotely sensible'.

No. The 34bhp Extrema is for committed nutters; fans of head-down, full-bore lOOmph momentumism. The Extrema is for those willing to coax unreal speed from puny power, then preserve it at all costs. The Extrema responds only when subjected to the uncompromising attack plan of a 125 grand prix racer: 1) peg throttle open 2) tread gear lever furiously 3) cling to speed like demented pitbull, and never let go. Dogged slipstream-ing, precision overtaking and ferocious corner speeds are the 125 racer's trademarks; buy an Extrema and they will become yours too, reality suspended forthwith.

It's all knees in, blue smoke and black visor. Ideally there's some Italian blood in the family tree. Move only when necessary and in measured amounts. Brake later, much later, and then brake less. Abuse the engine, caress the chassis or go in slow arid come out crawling. Rev it ruthlessly, all the time. Buy exotic two-stroke oils, never hesitate, relax or be embarrassed. Be in fact a short grand prix hero, and 50 times a day peek in the mirrors to check a policeman didn't witness what you just did.

This is life on the Extrema - outrageous fun, hopeless transport. To a real grand prix racer it's probably a slug, his humble paddock hack most likely, but just as the fastest GP bikes now come often as not from Italy, so indisputably "do the most authentic GP replicas. And if ever a road-going motorcycle were fit to receive a celebrated factory bottom, this is the one. Really, to use the Extrema as a plain motorbike is to ask the impossible.

Its heavenly curves and racy detail elevate it high above the 125 norm; a sprung front brake master cylinder, itself a mere thimble; myriad dinky button screws; and a total absence of cable guides and clutter score a desirability rating at least on a par with the RGV250. Big bike snobs may scoff, but in this unrestricted guise the Extrema (like the Cagiva Mito) is genuinely classless; no more a novice-friendly stepping stone than a Honda GoldWing. Gone are the days when having the 125 .business meant knocking out the restrictor and binning the L-plates. Graduated learners should ride a middleweight first - work up to the Extrema.

After all, it costs £3650, so should deliver like any other performance bike. There's plenty of bluffing (carbon fibre stickers etc) but you can't foist tat onto the huge and discerning Italian 125 market. An ally twin-spar frame, 40mm upside-down forks, a four-piston caliper, 320mm floating disc, and wide, 17in Dunlop radials are just for starters.

The grand prix derived touches are endless. By Japanese standards its fasteners and fittings are sparse and tiny; the opposed-piston rear caliper renders most efforts plain clumsy. The sprung to unsprung weight ratio takes on extra significance on a bike weighing just 115kg dry and the Extrema gives its suspension every chance by using scooped-spoke wheels unusually delicate by production bike standards^ The forks share one spring (left leg) and one damper unit (right leg) to counterbalance the front disc and caliper, and minimise steering inertia. And the Extrema is also serious about aerodynamics, the fairings have no sharp edges, only unexpected curves, while the underseat area is faired off to smooth the air flow around the rear wheel. Tucking in can send a labouring tacho needle singing into the red.

This, the RS125R version of the Extrema, is ostensibly an RS125, the short wheelbase beauty that succeeded the AF1 Sport Pro at the top of Aprilia UK's range, plus a carbon fibre exhaust can (wrapped round thin-walled ally), carbon fibre air ducts, and a polished metal finish on that dribblingly beautiful frame and swing-arm. It's an incredible piece of metal, neatly welded aluminium alloy spars cast into ribbed C-sections that are both light (9.75kg according to the frame sticker) and stiff beyond a 125's wildest performance dreams. The curva-ceously braced swing-arm, which replaced the old AF1-style mono-arm, is equally awesome and allows the Extrema to run a drastically short 1345mm wheel-base without a hint of instability. And that's the crux of the bike's handling. It doesn't steer with the nervous intensity of the Mito, but clings to the race-ready Cagiva by dint of its infallible precision.

It has, for a 125, big handling: lightness of touch but also a planted footprint which makes it less out and out fun than the Mito, but less of a toy too. The flattop tank, slotted and waisted for knees provides bracing without putting destabilising pressure on the wide bars, even under bonkers braking. The stubby pegs are high and rearset and make six footers as welcome as traditional 125 midgets. A full tuck is amazingly comfortable, in fact the whole chassis is a brilliant blend of lunacy, response, balance and security. Tracking the Mito at the Pembrey race track in Wales, I felt I could flick faster, and more accurately than Nige Breslain (easily the best Subbuteo player in my school).

 

Truth is, I couldn't. Returning from the medical centre I surmised that the steeply profiled Dunlops lend much needed zip to the steering, but their hard wearing compound dumped me out. The suspension, too, could use some damping adjustment as, on rougher surfaces, the rear shock got choppy and the forks, progressive enough on the immense but abrupt brakes, bounced back at the crucial turn in point. The Cagiva, meanwhile, was still thrashing round. Swallowing ZXRs whole.

The engine, unchanged from the AF1 series apart from unspecified port work, is just motion for the chassis. On paper it's all there — a compact liquid-cooled single, long life Nikasil plated barrels, RAVE exhaust valve and a lumpy 14.5:1 compression ratio - but is dwarfed by the handling. It sounds and revs like a 12bhp TZR125, vibrates despite a balance shaft, was stuffed out of sight by the Mito.

Moving from the free-revving (but fickle) Cagiva to the woolly Extrema was like losing a cylinder on a KR-1S twin, the crisp snap that makes all good two-strokes worth thrashing sadly absent. What the Extrema has though is proven reliability — use a good oil and it'll need re-ringing less often than a ZXR will need shimming. And what it does is click straight into life on the button (no kick-start), warm quickly and pull keenly enough from 6500rpm. As the two-stage RAVE shifts at 8100rpm, the hitherto •sterile exhaust note finally cuts an edge and the revs whizz up to the 11,000 before tailing off fast. In a lesser chassis that would be exciting, in the Extrema it's just enough.

Anyway, these 125 stand or fall on their gearboxes. The Extrema's uses the same internals as the Sport Pro which means three clonky lower gears and three sweet upper ones, spaced close enough for a shift at peak power at ll.000rpm to drop the needle at the top of the torque curve at 9000rpm. So despite a late and jerky clutch it's easy enough to keep the Extrema buzzing either in the useful 6-8000 range or up at boiling point. Our tester could reach 80 indicated mph anytime, though often only after dropping to fifth, and given a long enough stretch exploited its tall overall gearing to overhaul the Mito.

Who buys Extremas? According to Aprilia UK a typical customer is still to emerge even after selling 300 bikes since last August. "We've had plenty of younger blokes, as you'd expect," says Aprilia's Steve Reynolds, "but just as many older customers, including a 53-year-old farmer. I think the public now know what Aprilias are, a lot of credit has to go to the company's GP success." The RS/R version comes in at the same, price as the plain RS, maintaining Italy's relative advantage over the Japanese yen (TZR125: £3939). A free Abus goes to every Aprilia customer.

In spite of its intoxicating imagery and the obvious legal advantages of playing racers on a 125 in preference to a FireBlade, the Extrema still gets a tad tiresome when there are miles to be done or metropoli to be crossed. Presumably, all these mature customers have another bike for distance days, when 75 miles between petrol stops simply isn't enough.

The clearest advantage the Extrema has over the Mito is that, by comparison, it is positively staid. You can say no to its traffic light pleas for ll,000rpm and a screaming clutch. You can gurgle passed a policemen looking every inch the responsible motorcyclist. Then, when the going's good and that bout of sobriety evaporates, you can just pin it.

Tim Thompson

Source Bike 1994