A buzz, rattle or knock comes from the body of the bike: side panels, fairing, mudguards, number plate, seat, carrier or heat shield. It may appear at one engine speed, or only over bumps. Most rattles are a missing grommet, a broken tab or a loose bolt. The aim is to find it, then make sure the noise is not something more serious.
Is it safe to ride?
Yes, as long as nothing is about to fall off. A loose mudguard, number plate or carrier can drop into the wheel: fix those before riding.
Quick checks first
- Push and pull the mudguards, number plate, carrier, seat and side panels by hand.
- Look for missing screws and rubber grommets.
- Open the seat: is the toolkit or battery loose?
- Is a heat shield or chain guard loose?
Diagnose it step by step
1Does the rattle happen with the bike standing still and the engine running?
- Yes: it follows engine speed. Go to step 2.
- No, only when moving: go to step 3.
2With the engine at the rattling speed (on the stand, in neutral), touch panels and brackets lightly with a gloved hand one at a time. Does the rattle stop when you touch one?
- Yes: fix that part (Find and fix rattles).
- No, and it seems to come from the engine itself: see Ticking noise from the top of the engine or New or increased engine vibration.
3Does it rattle only over bumps?
- Yes: tap and shake each body part with the engine off. Check the seat (Seat is loose), the number plate, mudguards and the centre stand (Centre stand is hard to use or scrapes). If it is a clunk from the suspension, see Clunk from the rear suspension or Knocking or squeaking from the front forks.
- No, it follows road speed: go to step 4.
4Does it come from the rear wheel area and change with chain movement?
- Yes: the chain is hitting the guard or slider. Chain rubs on the guard, slider or swingarm.
- No: check the exhaust shields and mounts (Rattling from the exhaust or heat shield) and the mirrors (Mirror is loose).
5When you find it: is a tab broken, a grommet missing, or a bolt loose?
- Fix it: new grommets or well nuts, foam tape at contact points, tighten bolts (K-Light 125 body cover bolt: 9.0 N·m). Then Check chassis fasteners to catch other loose parts.
Causes, most likely first
| Cause | How to confirm | Fix |
|---|---|---|
| Missing grommet or loose panel screw | Rattle stops when panel is touched | Find and fix rattles |
| Broken panel tab | Panel moves, tab missing | Foam tape or new panel |
| Loose mudguard, number plate, carrier | Moves by hand | Fastener check |
| Loose heat shield | Buzz at one engine speed | Exhaust mounts |
| Chain hitting guard | Noise follows chain | Chain guides |