Description

KTM 400 LC4-E, 640 LC4-E, 640 LC4 ADVENTURE, 640 DUKE 2001 Parts Catalog

If you’ve ever ordered the wrong piston because some third-party parts list had the casting number off by one digit, you know the pain. This 40-page OEM KTM parts catalog is the factory document — not a reprint, not a scan of a scan. Printed in 2000 for the 2001 models, it covers the KTM 400 LC4-E, 640 LC4-E, 640 LC4 ADVENTURE, and 640 DUKE engines. Use it to confirm every bolt, gasket, and bearing before you call the parts counter.

Engine Case and Cylinder Head: Where the Real Work Happens

Page 3 of the catalog opens with the engine case (MOTORGEHÄUSE). You get exploded views with callouts for each part number. That includes the cylinder head (ZYLINDERKOPF) on page 8. Need the valve guide or a specific gasket? The part number is right next to the drawing. This is how you avoid ordering the wrong head gasket for a 400 versus a 640 — the bores are different. Valve components are listed separately under VENTILTRIEB on page 11. No guessing.

Crankshaft and Piston: Page 5 Specs You Can Trust

The crankshaft (KURBELWELLE, KOLBEN) on page 5 includes axial play specs: 0.03–0.12 mm. The piston’s diameter for the 400 cast cylinder is D=89mm; for the 640 forged it’s D=101mm. You won’t find those numbers in a Chilton manual. This catalog gives you the factory tolerances for the cylinder bore and the connecting rod bearing clearance. If you’re rebuilding a 640 LC4 Adventure, you need this page open on the bench.

Does It Cover the Carburetors and Ignition?

Yes. The catalog includes separate sections for the Dell’Orto PHM 38 ND (page 16) and the Mikuni BST 40 (page 18). You get the complete breakdown of jets, needles, and float parts. The ignition system (KOKUSAN) starts on page 20, and the electric starter on page 21. Everything ties back to the engine case drawings so you can cross-reference part numbers without flipping back and forth.

3 Reasons You Want OEM, Not Aftermarket

First, aftermarket catalog often combine multiple model years and drop the footnotes. Second, this manual uses Loctite 243 and Three-Bond gasket references that match the factory assembly line. Third, the “Spezialwerkzeug” page (page 29) lists the special tools KTM expects you to use — like the flywheel puller and the balancer shaft tool. Without those part numbers, you’ll end up rigging something and damaging the engine. Speaking of which, you might also need the 2001 KTM 125 SX MXC EXC Parts Catalog – OEM Factory Manual for other bikes in the shop.

Technical Data Engine: Page 31 – Don’t Skip It

The last two pages of the catalog list the TECHNISCHE DATEN – MOTOR. Crankshaft axial play, connecting rod radial play (max 0.05 mm), cylinder bore limits (max 89.04 mm for 400), and the balancer shaft specs. Write these limits on your shop board. If a part is worn past these numbers, it goes in the scrap bin. This is the kind of data you can’t get from a generic service manual. For a broader view of how OEM documentation fits into the Automotive Industry Overview, check that link, but for now, stick with the factory source.

Who Should Buy This Catalog?

If you’re a home mechanic rebuilding a 640 Duke engine in your garage, or a pro shop that sees a lot of KTM single-cylinder bikes, this catalog pays for itself the first time you avoid ordering the wrong crank bearing. Beginners: use this with a service manual. The parts catalog doesn’t tell you how to remove the cylinder — it tells you what part number the cylinder is. Pair it with the factory service manual. You can also look at the KTM 690 SMC 2008 Parts Catalog – OEM Factory Manual if you work on later models, or the KTM 690 SMC Parts Catalog – OEM Factory Spare Parts Manual for the SMC line.

FAQ

Does this catalog include the 400 LC4-E Supermoto?

Yes. The cover lists 640 LC4-E SUPERMOTO alongside the other models. All variants are covered in the same 40 pages. For example, page 5 shows the crankshaft and piston differences between cast and forged pistons. You’ll find part numbers for both the 400 and 640 engine cases on page 3.

What about the cooling system and water pump?

Wasswerpumpe (water pump) is on page 27, and the cooling system (Kühlsystem) is on page 28. Both sections give you the full parts breakdown with O-rings, seals, and impeller numbers.

Is the manual in English?

Yes. It’s a dual-language catalog (German/English). All headings, part descriptions, and technical data are in both languages. The torque specs and tolerances use metric units, as did KTM in 2001.

Can I use this for a 2002 KTM 640 LC4?

Not directly. 2001 was a transition year. The 2002 models had different crankshaft part numbers and a revised cylinder head. You need the 2002 catalog. This 2001 catalog is specific to the models listed on the cover: 400 LC4-E, 640 LC4-E, 640 Adventure, and 640 Duke. Part numbers changed after 2001.

You’ve seen enough aftermarket catalogs that leave you guessing. This 40-page OEM document is what the KTM factory used to build the engine. Get the correct part numbers, verify the tolerances, and stop wasting time on returns. Access the Factory Manual and keep it on your tablet or print it for the tool box.