KTM 390 Duke (2024+, 398 cc) Maintenance Schedule & Service Intervals
This is the maintenance schedule and service intervals for the KTM 390 Duke, KTM’s entry-level roadster, updated for 2024.
The original KTM 390 Duke (which went through a few minor evolutionary changes) was powered by a 373 cc single-cylinder engine.
The 2024 KTM 390 Duke is powered by a larger 398 cc single cylinder engine. It has much the same performance envelope, with peak power of 33 kW / 45 PS at 8500 rpm, but with more torque across the midrange.
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KTM 390 Duke (2024) Service Intervals
According to the manual, the 2024 KTM 390 Duke has service intervals of 6200 miles / 10000 km or annually. These are wider than the previous generation, which had 4650 mile / 7500 km service intervals.
At every service, you change the oil and filter, change the air filter, and spark plugs, and do a host of checks.
The major valve inspection is every 12400 miles or 20000 km (again, wider than the previous gen). There’s no time interval on the valve service.
Since the 390 Duke has a chain drive, make sure to regularly check it for condition and tension. Information on that is below.
Finally, the 390 Duke is a liquid-cooled bike, so change the coolant periodically. And keep the brake fluid up to date.
What you need to service your 2024+ KTM 390 Duke
Servicing your 390 Duke is fairly easy, relatively speaking. It’s a single-cylinder engine with an exposed engine. So when the valve service comes up every 20,000 km it’s not an overwhelming task for the home mechanic. The manual even provides the stock valve clearances!
Aside from basic motorcycle maintenance tools, here’s what you need to service your 2024+ 390 Duke.
Note some of these parts are updated since the previous model.
| Part | KTM 390 (2024+) Duke spec |
|---|---|
| Engine oil | The manual requires SAE 15W-50 oil that meets JASO T903 MA2 spec, and recommends Motorex oils, e.g. Motorex Top Speed 15W-50, a full synthetic. |
| Oil filter | Use a Hiflofiltro HF155 as a high-quality drop-in replacement. TBC |
| Spark plug | Standard spark plug is a Bosch VR 6 NEU. |
| Fork oil | Use SAE 4 fork oil. |
| Air filter | Use a K&N KT-1217 air filter. TBC |
| Brake fluid | Use a DOT 4 fluid e.g. Castrol DOT 4 full synthetic. |
| 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. (Most coolants contain at least phosphates or silicates… be wary) |
| Clutch cable lube | Use either engine oil or Protect all cable life, an affordable and quality lubricant. |
| Chain maintenance | Use Motul chain paste, a low-mess, high-quality chain lube. The manual recommends the more expensive Motorex chain lube. |
| Grease | Grease external parts with Motorex 2000 long-life lubricant per the manual, or any good lithium soap-based grease. |
Maintenance schedule for the 2024+ KTM 390 Duke
The schedule below comes straight from the manual for the 2024 390 Duke, though it has been restructured to make it easier to parse.
We’ve split the one big table into the standard service and the scheduled maintenance table, so you can easily see what to do every service, and what is only done occasionally.
KTM recommends most of the work be done by mechanics, and users only do the following:
- Check brakes (maybe replace if necessary)
- Check/adjust tyre pressures
- Check/adjust chain tension
- Check coolant and brake fluid levels
And very little else. Of course, servicing the 390 Duke isn’t hard as a single-cylinder mostly-naked bike, so it’s up to you.
KTM 390 Duke — Standard Inspection Checklist
Below is the inspection checklist for the KTM 390 Duke. Do this according to the schedule below.
Some items are marked [Dealer] as they need special equipment.
| KTM 390 Duke (2024) Standard inspection checklist |
|---|
| [Dealer] Read out the fault memory using the KTM diagnostics tool |
| Check that the electrical system is functioning properly (lights, switches) |
| Check the brake discs Front and rear disc minimum thickness: 4.5mm |
| Check the front brake pads for thickness and security (minimum thickness 1mm / 0.04 in) |
| Check the rear brake pads for thickness and security (minimum thickness 1mm / 0.04 in) |
| Check the brake lines for damage and tightness |
| Check the front brake fluid level (between lines) |
| Check the rear brake fluid level (between lines) |
| Check the tire condition (no damage, cracks) |
| Check tire pressure (see below for tire pressure specs) |
| Check the shock absorber and fork for leaks or damage |
| Check the chain, rear sprocket, and engine sprocket Not necessary at break-in service |
| Check the chain tension (see below for guidance) |
| Check the coolant level |
| Check the antifreeze / antiboil effectiveness (if you have the right equipment) |
| Check that the radiator fan is functioning properly |
| Chek that the throttle cables are undamaged, routed without kinks, and set correctly. |
| Check the cables for damage and that there are no kinks in the routing |
| Check all hoses (fuel, coolant, drainage etc.) and sleeves for cracking, leaks, and incorrect routing |
| Empty the drainage hoses |
| Grease all moving parts (e.g. side stand, hand lever, chain) and check for smooth operation |
| Check the tightness of the safety-relevant screws and nuts which are easily accessible. |
| Final check: Check the vehicle for safe operation and take a test ride. |
| [Dealer] Read out the fault memory after the test ride using the KTM diagnostics tool. |
| [Dealer] Set the service interval display. |
| [Dealer] Make a service entry in KTMDealer.net |
KTM 390 Duke Maintenance Schedule
Below is the scheduled maintenance table for the 390 Duke.
Notes
- Keep following the schedule in the pattern shown.
- Some items have a time-based schedule only (e.g. fluids), some a distance-based schedule only (e.g. valve clearance), but many items have both.
| mi x 1000 | 0.6 | 6.2 | 12.4 | 18.6 | 24.8 | |
|---|---|---|---|---|---|---|
| km x 1000 | 1 | 10 | 20 | 30 | 40 | Every |
| Conduct a standard inspection service (see list above) | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Change the engine oil (Motorex Top Speed 15W-50) | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Change the oil filter (HF155) | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Clean the oil screens | ✓ | ✓ | ✓ | ✓ | ✓ | Year |
| Clean the dust boots of the fork legs | ✓ | ✓ | ✓ | ✓ | ||
| Change the air filter (KT-1217), clean the air filter box. | ✓ | ✓ | ✓ | ✓ | ||
| Program the shift shaft sensor | ✓ | ✓ | ✓ | ✓ | ✓ | |
| Change the spark plug. (Bosch VR 6 NEU) | ✓ | ✓ | ||||
| Check the valve clearances. Intake: 0.10-0.15 mm / 0.0039-0.0059 in) Exhaust: 0.15-0.20 mm / 0.0059-0.0079 in) | ✓ | ✓ | ||||
| Check the frame (rust, cracks) | ✓ | ✓ | ||||
| Check the link fork | ✓ | ✓ | ||||
| Check the steering head bearing play (ensure ease of movement and no notchiness) | ✓ | ✓ | ✓ | ✓ | ✓ | |
| Check the fork bearing for play | ✓ | ✓ | ✓ | ✓ | ||
| Check the wheel bearing for play | ✓ | ✓ | ✓ | ✓ | ||
| Change the front brake fluid. (Motorex DOT 5.1, Castrol DOT 4) | 2 years | |||||
| Change the rear brake fluid. (Motorex DOT 5.1, Castrol DOT 4) | 2 years | |||||
| Change the coolant (Motorex Coolant M3.0) | 4 years | |||||
| Check the headlight setting | ✓ | ✓ | ✓ | ✓ | ✓ |
KTM 390 Duke (2024+) Tyre sizes and pressures
The KTM 390 Duke ships with the following tyre sizes and pressures.
| Wheel | Tyre size | Tyre pressure |
|---|---|---|
| Front | 110/70 ZR 17 M/C 54W TL | 200 kPa / 2 bar / 29 psi |
| Rear | 150/60 ZR 17 M/C 66W TL | 200 kPa / 2 bar / 29 psi 220 kPa / 2.2 bar / 32 psi with passenger |
The 390 Duke ships with either Metzeler Sportec M9 RR or Michelin Power 6 tires stock.
KTM 390 Duke Chain Maintenance
KTM recommends you regularly clean the chain and check / adjust its tension for all their bikes.
To check the tension on a KTM 390 Duke, you measure the distance between the chain and the link fork (not the free movement of the chain, like on other bikes).
To measure tension on your KTM 390 Duke:
- 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)
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 — 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 worn.
About the KTM 390 Duke (2024 update)
The KTM 390 Duke is an entry-level “roadster” motorcycle from KTM. But you get a lot of value for money!
For over a decade, the 390 Duke has been known as a super lightweight fun roadster. It’s an “almost supermoto” in that it has a comfortable riding position and unbelievably, toy-like low weight — it’s 165 kg fully fuelled.
For people in the US, the 390 Duke is seen as an entry level roadster before a step up to the 790/890, or even the Super Duke R (which KTM contemporaneously updated to the KTM 1390 Super Duke R).
But in Europe, the 390 Duke is a common fun bike, ideal for twisty switchbacks. And in India (outside the wealthy big cities) it’s seen as a big bike, especially alongside the KTM 125, 200, and 250 Duke! There’s a Duke for everyone.
For 2024, KTM has updated the KTM 390 Duke’s engine to a 398 cc single, up 24 cc from the 373 cc of its predecessors. The power is much the same, but with more midrange. It makes 33 kW / 45 PS at 8500 rpm, with torque peaking at 7000 rpm.
In recent years, KTM had already given the 390 Duke loads of high-end gear. The suspension has a high degree of adjustability, with rebound and compression adjustability at the front, and rebound and preload adjustability at the rear.
There’s a slipper clutch, and unbelievably, there’s even cornering ABS — giving unparalleled confidence to new riders in the price bracket.
The display is a 5-inch TFT (now de rigueur in most new motorcycles).
One secret weapon of the KTM 390 Duke (for a few recent generations) is “Supermoto ABS”, which lets you disable rear ABS — on a road bike, this gives options for a lot of shenanigans, including controlled power slides! Find another learner-legal bike with that feature… aside from the smaller and surprisingly high-spec 2024 KTM 125 Duke, of course.
Reference: Manual for the KTM 390 Duke (2024)
The above maintenance schedule came directly from the 2024 manual for the KTM 390 Duke.
You can download the manual directly from KTM here.
