Check exhaust mounts and heat shields

The exhaust hangs from the engine at the front and from the frame or footpeg bracket at the rear, often through rubber bushes. A heat shield is a thin cover screwed or clamped to the pipe to protect your leg. Mounts and shield screws shake loose, rubber bushes perish and brackets crack. The result is a rattle, a buzz at certain revs, or a pipe that touches the frame. The K-Light schedule asks for the muffler to be inspected at every service.

Safety

• Do this with a cold exhaust only.
• A loose exhaust can drop onto the road or touch the rear tyre or chain. Do not ride with a pipe hanging loose.
• A heat shield that falls off leaves a very hot pipe next to your leg and luggage.

You need

• Spanners or sockets for the mount bolts, screwdrivers for shield screws.
• Replacement rubber bushes or shield screws (stainless screws resist rust).

Steps

1. With the engine cold, grip the silencer and shake it gently up and down and side to side. Listen and watch for movement at the front flange, the middle clamp and the rear mount.
2. Look at the rear mounting bolt and its bracket. Check for a missing nut, a worn rubber bush or a crack in the bracket.
3. Tap each heat shield with your knuckle. A buzz or rattle means loose screws or a broken clip. Check that each screw is present and tight.
4. Look for marks where the pipe or shield touches the frame, the stand, the brake pedal or the bodywork. Shiny rubbed spots show contact.
5. Tighten loose mount bolts to the manual value. K-Light 125: muffler mounting bolt 22 to 29 N·m.
6. Replace hard or split rubber bushes. Refit missing shield screws with a washer. If a shield clip has broken, use a stainless hose clip as the maker supplies or a new shield.
7. Start the engine (outside) and listen at idle and at the revs where the rattle was worst.

Check your work

• No movement at the mounts when you shake the pipe.
• Shields silent when tapped.
• Pipe clears the frame, stand, chain and tyre.

If it did not fix the problem

• Rattle comes from inside the silencer (a loose baffle): the silencer needs repair or replacement. See Exhaust has become much louder.
• Rattle from elsewhere on the bike: Find and fix rattles.
• Ticking at the front joint: Find and fix an exhaust leak.
• Bracket cracked on the frame: Crack in the frame or a bracket.

Reference values (K-Light 125)