The handlebar needs more effort to turn than it used to, especially at low speed, or it does not return to straight by itself. The most common cause is a soft front tyre. Others are steering head bearings that are too tight, dry or rusty; cables or hoses that pull tight when you turn; a worn or wrong-size front tyre; or forks that are twisted or bent.
Is it safe to ride?
Ride with care to check the tyre. If the steering is suddenly heavy (puncture), or it binds at one point, do not ride.
Quick checks first
- Check the front tyre pressure now (K-Light 125: 190 ± 10 kPa cold).
- Look for a nail or cut in the front tyre.
- Turn the bars lock to lock with the engine off: do any cables or hoses pull tight?
- Has a new, wider or different front tyre been fitted?
Diagnose it step by step
1Is the front tyre soft or punctured?
- Yes: inflate and check for leaks. See Tyre slowly loses air and Check tyre pressure.
- No: go to step 2.
2When you turn the bars, does a cable, hose or wire go tight or catch?
- Yes: reroute it so it moves freely at full lock. The K-Light 125 manual includes this check. A tight throttle cable also changes the idle when you steer: see Throttle sticks or does not snap shut.
- No: go to step 3.
3Lift the front wheel off the ground. Do the bars fall freely to each side from the centre?
- No: the steering bearings are too tight, dry or damaged. Check the steering head bearings and then Adjust or replace steering head bearings.
- Yes: go to step 4.
4Do the bars catch or click at one point (usually centre)?
- Yes: dented races. Go to Steering is notchy or catches in the centre.
- No: go to step 5.
5Is the front tyre worn flat in the centre, squared off, or a different size from the manual?
- Yes: replace with the correct size. Inspect tyres for wear and damage.
- No: go to step 6.
6Are the forks straight and equal, and was the bike recently dropped?
- Twisted: Align the front wheel, forks and handlebar.
- Bent or after a crash: workshop. See Inspect the frame after a crash.
Causes, most likely first
| Cause | How to confirm | Fix |
|---|---|---|
| Low front tyre pressure | Gauge reading | Check tyre pressure |
| Cable or hose pulling at lock | Tight when bars turned | Reroute |
| Steering bearings too tight or dry | Bars do not fall freely | Adjust or replace steering head bearings |
| Dented bearing races | Notch at centre | Adjust or replace steering head bearings |
| Worn or wrong front tyre | Flat centre; wrong size | Inspect tyres for wear and damage |
| Twisted or bent forks | Legs uneven | Align the front wheel, forks and handlebar |
Reference values (K-Light 125)
| Item | Value | Source |
|---|---|---|
| Front tyre cold pressure | 190 ± 10 kPa | K-Light 125 manual, PDF p. 71 |