Due to the light weight the RS4 handles brilliantly. Flicking it from right to left is a doddle and should you need to change your line during a corner, a slight push on either bar will suffice. The launch bikes were shod with super-sticky Pirelli SC1s which really showed off the full handling potential of the RS4. It's surprisingly roomy and, compared to the old RS125, feels slightly less sporty which is a big plus.
Pulling away requires a good twist of the wrist to get the new four-valve, four-stroke engine spinning and keep up the momentum. Compared to some 125s the RS4 needs to be revved and ideally kept above 8000rpm. Even som the Aprilia accelerates briskly upto 40mph before starting to level off.
The new four-stroke 125cc engine should be much more reliable than the highly-strung two-stroke engine of the old RS - which was often neglected by teenagers. The bikes never missed a beat being held at full throttle virtually all day in 30°C plus heat.
£3999 on the road sounds like a lot for a 15bhp bike, but when you consider the Yamaha YZFR-125, arguably its closest rival, costs £4,249 it doesn't seem so bad. Yes, there are cheaper 125s out there, but none of them are as cool as the Aprilia.
Radial brakes, braced swingarm, max speed function and braided hoses are all standard on the RS4 125. One of the accessories which will beavailable is a quickshifter. It only really works weel if changing up right before the rev limiter at 11,000rpm, changing anywhere else results in a very clunky and crude sounding gear change. But a quickshifter will give you major bragging rights over your mates.