Rear suspension feels harsh

Bumps come straight through the seat with a jolt, as if the rear does not move enough. It can be set too stiff (preload too high for a light rider, tyre pressure too high), or something is stopping it moving: a seized swingarm pivot, seized shock mount bushes, or a damper that has locked up. A rear that sits so low it hits its stops also feels harsh.

Is it safe to ride?

Ride with care. A rear that does not move loses grip over bumps.

Quick checks first

• Check rear tyre pressure (K-Light 125: 210 ± 10 kPa cold).
• What preload step are the shocks on? Is it the highest with no load?
• Push down on the seat: does the rear move at all, or very little?
• Does it feel harsh only with a passenger?

Diagnose it step by step

1Is the rear tyre over-inflated?

• Yes: set it with Check tyre pressure.
• No: go to step 2.

2Is preload set high while riding alone with no load?

• Yes: lower it a step (both sides the same) with Adjust rear spring preload.
• No: go to step 3.

3Does it feel harsh mainly with a load, as a hard knock on bumps?

• Yes: the rear is bottoming. Go to Rear sits too low.
• No: go to step 4.

4When you push hard on the seat, does the rear move only a little and stiffly?

• Yes: go to step 5.
• No: check the seat foam and seat mounts; a flattened seat feels harsh too.

5Support the bike with the rear wheel off the ground. Is the swingarm pivot or a shock mount seized?

• To check, follow Check the swingarm pivot and Check the rear shock absorbers. A pivot that does not move smoothly needs cleaning, greasing or new bushes.
• If the pivot moves freely with the shocks disconnected but the shock is very stiff, the damper has seized. Replace the shock (both, on twin shocks).

Causes, most likely first

Reference values (K-Light 125)