Correct chain slack on the KTM 790 Adventure is 2-5 of vertical movement, measured midway between the sprockets. Too tight and you load the countershaft bearing and suspension; too loose and the chain can slap, jump, or wear the sprockets unevenly.
Check slack every 500-1,000 miles and after any rear-wheel work. You’ll need the bike upright (not on the side stand) for an accurate reading.
KTM 790 Adventure quick service specs
| Item | Specification |
|---|---|
| Engine oil | Motorex Power Synthetic 4T 10W/50 (JASO MA2) |
| Oil capacity | 2.8 liters |
| Oil change interval | 9300 miles |
| Chain slack | 2-5 mm |
| Spark plug | NGK LMAR9AI-10 |
| Tire pressure (F/R) | 35 PSI front / 35 PSI rear |
| Battery | your owner’s manual |
How to adjust chain slack, step by step
- Put the bike on a paddock stand or center stand so the rear wheel is off the ground and the suspension is unloaded.
- Find the tightest point: rotate the wheel and push the chain up and down midway between the sprockets.
- Measure vertical movement with a ruler or chain tool — push the chain up, then down, and measure the total travel.
- Compare to the 2-5 spec. If it’s out of range, loosen the rear axle nut.
- Turn both chain adjuster bolts equally — count flats or use the alignment marks so the wheel stays straight.
- Re-check slack at several points by rotating the wheel; chains have tight spots. Set slack at the tightest point.
- Tighten the axle nut to the factory torque spec, re-check slack once more, and make sure the adjusters are locked.
Common mistakes to avoid
- Adjusting on the side stand — the suspension compresses differently and you’ll set it too tight.
- Adjusting only one side — a crooked wheel eats chains and sprockets.
- Setting slack at a loose spot — always find and set at the tightest point.
FAQ
How often should I check chain slack on the KTM 790 Adventure?
Every 500-1,000 miles, before long trips, and after any rear-wheel removal. It only takes a minute.
What’s the correct chain slack for the KTM 790 Adventure?
2-5 mm of vertical movement at the mid-point between the sprockets, measured with the bike upright and the suspension unloaded.
Can I ride with a slightly loose chain?
A little loose is safer than too tight — a tight chain overloads the countershaft bearing. But excessive slack can jump teeth, so stay within spec.
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Dan Heiman
Writer at Helmet Today, covering helmet reviews, fit and riding safety.
