Description

Aprilia RS 125 2003 Parts Catalog

If you are trying to restore or repair an Aprilia RS 125 from the 1999-2003 generation, you already know the problem. Aftermarket parts diagrams are a guessing game. One wrong part number and you are waiting two weeks for a piston that doesn’t fit. This is the factory Aprilia RS 125 2003 Parts Catalog — 86 pages of exploded views and OEM part numbers. No cross-references to vague aftermarket supersessions. You get the exact code the dealer uses. That is the difference between a parts order that arrives right and a box of useless metal.

Frame and Chassis Components

The catalog starts with the frame and central stand (sections 1-2). Page 3 lists every fastener and bracket for the main frame: split pins, special bushes, hex socket screws, and rubber spacers. You get the exact part code and quantity per bike. If you are building a frame from scratch or replacing crash-damaged parts, this section pays for itself in one order. The exploded view shows how the lateral stand plate differs between CH-EU-SGP and other markets — a detail aftermarket diagrams miss completely.

Does This Catalog Cover the Engine and Carburetor?

Yes. Sections 24 (Engine), 39 (Cylinder – Head – Piston), 41 (Cylinder – Exhaust valve), 42 (Transmission), and 21-23 (Carburettor I, II, III) are all included. The carburetor section alone has three separate pages because the Aprilia RS 125 uses a complex Dell’Orto setup with multiple gasket and jet variations. You will find the correct part number for the carburetor flange (section 40), water pump assembly (37), and oil pump (46). This is not a service manual — it will not tell you how to tune the carb. But it will tell you exactly what part number to order when a jet needle wears out.

86 Pages of OEM Part Numbers

Count them: 86 pages. That sounds thin until you realize every page is packed with a parts table and an exploded diagram. The electrical section alone covers sections 30 (Lights), 31-32 (Electrical system I & II), and 47 (Ignition unit). If you are chasing a no-spark issue and need the CDI unit or stator, the part numbers are here. The lock hardware kit (section 33) and decal set (35) are also cataloged — things most aftermarket sources ignore.

Verify Part Numbers Against Your VIN

Before you order anything, pull your VIN and check the “Versjon” column in the parts table. The catalog includes market-specific variants (A, AA, AUS, B, CH, D, DK, E, EU, F, GR, I, J, JJ, NL, P, S, SF, SGP, UK). For example, the lateral stand plate (section 2) differs between the CH-EU-SGP version and the rest. Ordering the wrong one means a stand that doesn’t hit the ground correctly. That is a safety issue, not a minor inconvenience. Use the factory data to get it right the first time.

Source Authenticity: OEM vs. Aftermarket

This catalog comes from the original Aprilia factory PDF, not a scanned reprint or a third-party compilation. The table of contents points to www.aprilia.no — the official Norwegian distributor site, which accessed the same database dealers use. I have seen aftermarket manuals where the part numbers are off by one digit or the diagram is reversed. That does not happen here. Every pos. number in the table matches the exploded view. Every code (e.g., 8135998 for the frame) is Aprilia’s own. When you are ordering a £300 crankcase, you want that certainty. For context on why factory documentation matters in any motor vehicle repair, read the Automotive Industry Overview and Automotive Industry Overview.

Cylinder – Head – Piston: Critical Dimensions

Section 39 is dedicated to the cylinder, head, and piston assembly. This is the heart of the two-stroke engine. The parts catalog lists every gasket, ring, and pin. If you are rebuilding after a seizure, you need the correct piston grade and circlip part number. Aftermarket catalogs often list a generic piston that “fits” but the pin size or ring gap may be wrong. This factory page tells you exactly what Aprilia installed at the factory. Pair this with the workshop manual for torque specs — grab the Aprilia RS 125 Workshop Manual – Factory Specs for 2-Stroke alongside.

7 Systems Covered: A Quick Reference

1. Frame & stand
2. Front & rear footrests
3. Front fork & swing arm
4. Engine & transmission
5. Carburetor & air box
6. Electrical & lighting
7. Bodywork & decals

That is not a complete list — the catalog covers 47 sections total. But these seven groups cover 90% of the parts you will ever need on an RS 125. The fuel tank, saddle unit, exhaust unit, and rear brake are all inside. If you are sourcing parts for a full restoration, this single document is your bible.

Related Manuals

• Aprilia RSV Mille 2000 Parts Catalog – for the V-twin sibling.
• Aprilia RSV mille 1999 Training Manual – technical training documentation.

Does this catalog include exploded diagrams?

Every section has a one-page exploded view with numbered parts. The table on the facing page lists each part’s code, description, and quantity.

Can I use this to order parts from a dealer?

Yes. The part numbers are OEM and match what the dealer’s system shows. Show the dealer the code (e.g., 8121999 for the stand pin) and they can order it.

What years does this cover?

This catalog covers Aprilia RS 125 model years 1999-2003. The title says 2003 but it includes all earlier revisions up to that year. Always cross-check your frame number against the variant codes in the tables.

Is there a supplement for later models?

This catalog covers the RS 125 model years 1999 through 2003. Aprilia released an updated parts catalog for the later models, but for the 99-03 generation this is the definitive factory document. If you own a 2004 or later RS 125, you need a different catalog. The 2003 edition includes all revisions up to the end of production, so it supersedes earlier printings. Always verify your frame number against the parts list to avoid ordering components for a different sub-model.

Stop wasting time with generic aftermarket diagrams. Access the Factory Manual and get the exact part numbers you need for your Aprilia RS 125. 86 pages of OEM data, ready to print or use on your phone in the garage.