this was taken from a website. hope all aprilia owners find it
useful.
Tips for stock (standard) RS125 :
Use a good quality 100% Synthetic Oil, preferably Silkolene Comp
2+, Motul 600, Castrol TTS or Shell Advance VSX RacingX or M.
Change the original spark plug for a Racing one. Use a NGK B10EG
or B10EG-V
Use 98 octane fuel.
Every 4000KM, de-carbonise the cylinder and clean the exhaust
valve to ensure smooth running.
Use a good quality synthetic gearbox oil like Motul, Castrol or
Mobil.
Oil the with Chain WAX and not chain OIL every 250KM
Clean the bike and perform regular maintenance on it (like oiling
cables, etc..)
More modifications :
Drop the forks down through the yokes by about 1.5CM for an
increased angle of attack and a faster turn in speed
Use a thicker fork oil for the front forks
Fit a set of EBC "Double-H" sintered brake pads for MUCH BETTER
braking. the reference number for the front pads is : EBC
AF126HH
Fit braided brake lines to compensate for the extra heat produced
by the sintered pads
Replace the stock carburettor for a Dell'Orto 34mm one.
Replace the standard exhaust for an Arrow or Giannelli exhaust
system
RS125 Restrictions
Let's clear the subject of restriction's up to avoid any confusion!
There are 2 (TWO) types of restrictions that the RS125 can have
:
The first restriction is a power restriction, it will limit the
RS125's maximum power to 15bhp (or 11kW). The restriction consists
of the lack of a Powervalve (instead a blanking plate is fitted so
there's a fixed exhaust port height), Powervalve electric motor
(opens the powervalve), Powervalve control unit, some sort of
exhaust restriction (the pipe diameter is restricted with some sort
of insert into the exhaust) and the matching carburation changes to
reflect the restriction. This restriction is only found on some
RS's (the 15bhp or 11Kw versions) to make it legal for 16 year olds
to ride it in some countries. If your bike can only do about
120-130KM/H and there isn't a sudden power increase at about
8-9,000rpm then it's probably restricted. Another way to check for
the lack of a Powervalve is to put the bike into neutral and keep
it idling, then rev it slowly to about 3,500rpm. At about 2,500rpm
you should hear a clicking sound from the engine. This sound is the
powervalve closing and opening. If you don't hear any of this, then
your bike hasn't got a powervalve. Take a look at the powervalve
picture at the bottom of the page,
The second restriction causes the power dip between 5,000-6,000rpm
and it does this by retarding the ignition (spark) in this rev
range. This is done so that the RS125 (being a 2-stroke) can be
homologated and pass the new European Union emissions and sound
tests. This can be removed by modifying the CDI. I've done this
myself and it makes the bike much easier to ride around town as you
don't have to slip the clutch or go down a gear to get into the
powerband. The old RS125 ('98 and before - Rotax 123 engine) didn't
have this restriction. Read below on how to de-restrict the RS125
CDI.
