KTM 125 Duke (2024) Maintenance Schedule / Guidelines
This is the maintenance schedule for the KTM 125 Duke made from 2024 with the SOHC engine.
The KTM 125 Duke is a continuation of the 125 Duke line, originally made in 2011 through to 2022 (see the maintenance schedule for the original 2011-2023 KTM 125 Duke).
But the 2024 KTM Duke is a comprehensive overhaul, with a new look, engine head design, and suite of tech features. It shares a lot in common with its bigger sibling the 2024 KTM 390 Duke, down to the ride aid electronics.
The 2024 KTM 125 Duke is powered by a 125 cc engine with a (very) slightly longer stroke per the specs in the manual. The four-valve head is driven by a single overhead cam, with the valves controlled via rocker arms. (KTM’s revised 2024 250 Duke retains DOHC, as does the 390.)
The final drive is via six-speed box and chain.
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KTM 125 Duke Service Intervals
Overall, the KTM 125 Duke has service intervals of 4,650 miles / 7,500 km or one year. At every service, engine oil and filter, and do a once-over of the motorcycle, checking and greasing various parts (listed below in the annual service checklist).
The valve service is every 9,300 miles / 15,000 km with no time interval. At the same time, change the spark plug.
Since the little 125 Duke has a liquid-cooled engine, KTM recommends changing the coolant every 4 years.
Finally, make sure you keep your chain maintained — there’s guidance on how to do this below.
What You Need to Service your KTM 125 Duke
Below are the parts and consumable liquids you need to service your KTM 125 Duke.
| Item | KTM 125 Duke Spec |
|---|---|
| Engine oil | SAE 15W/50 partially synthetic, ideally Motorex Formula 4T 15W/50 |
| Oil filter | Hiflofiltro type HF155 |
| Spark plug | Champion REK6ZMC Gap: 1mm / 0.04 in |
| Air filter | K&N type KT-1217 air filter |
| Cable mainteancne | Use Protect All Cable Life, a well-liked and affordable cable lube |
| Brake fluid | DOT 4 or DOT 5.1, e.g. Castrol DOT 4 or Motorex DOT 5.1 |
| Chain lubricant | Motorex Chain Cleaner / Motorex Chain Lubricant |
| Coolant | The manual calls for Motorex Coolant M3.0, which is an OAT coolant based on ethylene glycol that’s silicate, nitrite, amine, borate, and phosphate free. |
KTM 125 Duke Maintenance Schedule
Below is the maintenance schedule for the 2024 KTM 125 Duke.
It’s in a simpler format than the one in the owner’s manual, separated out into a “major items” checklist, plus an annual service checklist.
KTM 125 Duke Maintenance — Major Items
Below is the major items maintenance schedule for the KTM 125 Duke. Note that rather than 4,650 miles, for simplicity, the schedule is below in intervals of 4,500 miles.
At the end of the maintenance schedule, repeat it in the pattern shown.
| mi x 1000 | 0.6 | 4.5 | 9 | 13.5 | 18 | |
|---|---|---|---|---|---|---|
| km x 1000 | 1 | 7.5 | 15 | 22.5 | 30 | Every |
| Standard maintenance checklist (see below) — Perform all items (Note: Some items are excluded at break-in, see below) | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Engine oil — Change | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Oil filter — Change. Clean the oil screen as well. | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Air filter — Change. Clean the air filter box. | ✓ | ✓ | ✓ | ✓ | ||
| Spark plugs — Replace | ✓ | ✓ | ||||
| Valve clearances — Check / Adjust | ✓ | ✓ | ||||
| Brake fluid (front and rear) — Change | 2 years | |||||
| Coolant antifreeze — Check level and effectiveness | ✓ | ✓ | ✓ | ✓ | 2 years | |
| Coolant — Change | 4 years | |||||
| Steering head bearing — Check for play | ✓ | ✓ | ✓ | ✓ | ✓ | |
| Fork bearing — Check for play | ✓ | ✓ | ✓ | ✓ | ||
| Wheel bearing — Check for play | ✓ | ✓ | ✓ | ✓ | ||
| Headlight setting — Check | ✓ | ✓ | ✓ | ✓ | ||
| Fork legs — Clean dust boots | ✓ | ✓ | ✓ | ✓ | ||
| Frame — Check | ✓ | ✓ | ||||
| Link fork — Check | ✓ | ✓ |
Standard Inspection Checklist
Below is the annual checklist for the KTM 125 Duke. Do these checks/service items according to the maintenance schedule above.
Notes
- [Dealer] marked items need specialist dealer tools.
- # items not required at break-in — but are simple to perform.
| KTM 125 Duke Annual Service Checklist |
|---|
| [Dealer] Read out the fault memory using the KTM diagnostics tool. |
| [Dealer] Program the shift shaft sensor. |
| Check that the electrical system is functioning properly. |
| Check the front and rear brake pads. |
| Check the front and rear brake discs for warp and wear. |
| Check the brake lines for damage and tightness |
| Check the front and rear brake fluid levels. |
| Check the shock absorber and fork for leaks. Perform service as needed and depending on how the vehicle is used. |
| Check the steering head bearing for play. |
| Check the tire condition |
| Check tire pressure (see below table) |
| Check the rim run-out |
| # Check the chain, rear sprocket, and engine sprocket. |
| Check the chain tension (see below guidance) |
| Check the cables for damage and routing without sharp bends |
| Check the coolant level |
| Check that the radiator fan is functioning properly. |
| Grease all moving parts (e.g. side stand, hand levers, chain) and check for smooth operation. – Use lithium soap-based grease for major moving parts – Use Motul chain paste for the chain |
| Check all hoses (fuel, coolant, bleeder, drainage etc.) and sleeves for cracking, leaks, and incorrect routing |
| Check that the throttle cables are undamaged, routed correctly (without sharp bends), and set correctly. |
| Empty the drainage hoses |
| Check the tightness of the safety-relevant screws and nuts which are easily accessible. |
| Check the antifreeze |
| Final check: Check the vehicle for safe operation and take a test ride. |
| [Dealer] Set the service interval display. |
| [Dealer] Read out the error memory after the test ride using the KTM diagnostics tool. |
| [Dealer] Make a service entry in KTMDealer.net |
KTM 125 Duke Chain Maintenance
As a common everyday commuter bike, the KTM 125 Duke’s chain is likely to see a lot of use — so tend to it regularly. Basic maintenance for the chain includes
- Cleaning and lubricating the chain
- Checking the chain for wear/damage
- Adjusting the chain tension
Clean and lubricate the chain with chain lubricant. A well-recommended and affordable one is Motul chain lubricant, or Motul chain paste for a portable option.
To check the tension on a KTM 125 Duke, you measure the distance between the chain and the link fork (not the free movement of the chain, like on most other bikes).
To measure chain tension on your KTM:
- Put the transition into neutral
- Raise the rear wheel
- Press upwards on the chain near the chain guard.
- Measure the distance between the middle of the chain and the link fork.
- Repeat the measurement for various parts of the chain (chain wear can be uneven)
Target chain tension for the KTM 125 Duke: 5-7 mm (0.2-0.3 in)
To adjust the chain tension, you need to release the rear axle, slide it forwards or backwards, and then re-tighten it.
- Loosen the rear axle nut.
- Loosen the lock nuts for the adjusters on both sides of the axle.
- Turn the adjuster screws to move the axle position. If you’re reducing tension, you may need to physically move the wheel to make sure it’s moving with the screws.
- Make sure you turn them the same amounts (checking the reference marks)
- Re-righten the lock nuts (not too tight)
- Tighten the rear axle nut (very tight, even on this little bike — 100 Nm / 74 lb-ft)
If you can’t get the chain tight enough, then it may be too worn. To check its wear state, hang a 15 kg / 33 lb weight off the lower section of the chain. Measure the distance between 20 rollers (counting 1 through 21), in a few parts of the chain. The maximum length should be 301.6 mm or 11.9 inches. If it’s longer, then your chain is too worn, and you should replace it along with the sprockets.
Wheels and Tires
The KTM 125 Duke ships with a 17 inch front and rear tire combo and with Michelin Road 5 tires or Metzeler Sportec M9, depending on market.
| Wheel | Rim size | Tire size | Tire pressure (cold) |
|---|---|---|---|
| Front | 110/70 ZR 17 M/C 54W TL | 2.0 bar / 29 psi | |
| Rear | 150/60 ZR 17 M/C 66W TL | 2.0-2.2 bar / 29-32 psi |
About the KTM 125 Duke (2024)
The 2024 KTM 125 Duke is a significant revamp of KTM’s beginner — but not cheap — motorcycle.
It’s not “cheap” in the sense that it’s not low-quality. The KTM 125 Duke has a finish that’s similar to other, bigger motorcycles from KTM’s range, including the KTM 250 Duke (limited markets) and KTM 390 Duke, at least.
Nor is it “cheap” in the sense that KTM has skimped on parts. Sure, the suspension might lack the adjustability that higher-end bikes have. But the KTM 125 Duke still has a TFT display and a full electronics suite of rider aids — including cornering ABS.
Finally, the KTM 125 Duke is by no means the cheapest bike on the market! There are more affordable 125 cc entry-level options out there for sure.
There’s a lot to like about the KTM 125 Duke. It shares a chassis and general look/profile with its much bigger 390 Duke sibling, but is even lighter thanks to its 125 cc engine with a single overhead camshaft.
Apart from tech, there’s a lot of other stuff in the 125 Duke that’s high-spec. It has ride by wire and a slipper clutch. The brakes are even the same as on the 390 Duke, with a 320 mm disc and four-piston radial-mount ByBre caliper. You can even get a quickshifter on the diminutive Duke. A factory quickshifter! On a 125 cc street bike!
Like the other new KTMs, the 125 Duke has “Supermoto” ABS mode, which means you can disable rear wheel ABS. This means you can slide it around willy nilly, if that’s your style of riding.
The only thing it lacks is outright power. The 125 Duke makes 11 kW / 15 hp at 10,000 rpm — the legal maximum in markets where sub-125 cc have a different license class. You might note that other small bikes (like the Grom) make similar power.
Reference — Screenshots from the 2024 KTM 125 Duke Manual
Below are screenshots from the manual for the 2024 KTM 125 Duke. You can check some of the above from this content.
You can get manuals for KTM motorcycles from KTM directly.
