The brake change in 2006 is as hard a parts split as the 122 and the 123. Axial calipers through the bee-tail, to 2005. Radial calipers and braided lines on the RSV-style bike. The Euro 3 bike keeps that look. The four-strokes are not described. Order pads for the caliper you can see, not for the year in the advert.

Seized pistons

A caliper that pulls to one side, or a pad that is half worn, is often a piston that no longer moves. Take the pads out. Use a gentle pedal or lever to move the piston a few millimetres, with a block of wood in the way so it cannot leave the bore. If it will not move, do not put the full lever on it. A piston that exits the bore on the garage floor is a fluid spill and a rebuild.

Clean the exposed piston with brake cleaner and a soft cloth. Pitting under the dust seal means a new piston, not a polish. The seal kit and the piston diameter are To verify. Lever the dust seal out with a plastic tool. A screwdriver that slips lands in the piston.

Push the piston back only after you have taken fluid out of the master cylinder. Forcing it back sends dirty fluid up the line and can overflow the reservoir onto the paint. Paint and brake fluid do not mix. If fluid hits a panel, wash it with water now, not after you have been for a test ride.

Fluid

The grade is To verify on the cap. Do not assume DOT 4 because many bikes use it. If the cap is missing, use the manual, not the bottle that was already on the shelf. Fluid from an open bottle that has sat for a year has already absorbed water. Buy small.

Bleed at the nipple the manual shows, farthest first if there are two. Keep the reservoir topped up so you do not suck air. A clear hose lets you see the bubbles. Nipple torque is To verify. A nipple wound in on its threads until it strips is a new caliper.

Braided lines from 2006 are a sourced fitment, not a fashion note. Earlier hoses: inspect them, and replace perished rubber. The original construction is To verify. Banjo washers are single-use in any careful rebuild. Torque is To verify.

The rear brake

The brief does not say whether a given generation has a rear disc or a rear drum. To verify before you buy shoes or pads. Look at the wheel. A cable or a rod that is seized in its adjuster is an MOT failure you can see without a parts catalogue. Free it, or replace the cable. Do not ride with the rear brake dragging. A dragging brake on a two-stroke that already runs hot is a seized engine waiting at the lights.

After assembly

Pump the lever until it is firm before the wheel goes back in the shed, and again before you roll the bike. A soft lever on the road is the bleed, or a leak at a banjo you can see if you look. Bed new pads with a series of gentle stops. The compound is To verify, so there is no bedding ritual from the brief beyond “do not get them hot and glazed on the first mile”.

Disc thickness and minimum pad thickness live in the manual and in the current MOT inspection manual. This site does not copy a millimetre it has not taken from those pages.