The silencer is one of the most visible parts of a motorcycle and also one of the dirtiest. Carbon, soot, chain lube fling, road dirt and moisture soon make it dull, and oxidation and rust follow.
Regular care brings back the shine and keeps corrosion at bay, especially after a season of rain and damp nights in the garage. Here is the full cycle, from removing the silencer to polishing and protection.
What you will need
Important: Start only when the engine and exhaust are completely cold. Use abrasive paper wet only, and only on unpolished stainless or mild steel: carbon, heat-tinted titanium, chrome and painted silencers must not be sanded.
Step 1
Remove the silencer
It is far easier to clean off the bike. Undo the clamp at the link pipe, then the mounting bolt, and work the silencer free. If the bolts are seized, treat the threads with WD-40 Specialist Penetrant and wait a few minutes. A tight silencer can be eased off with light taps of a rubber mallet.
Step 2
Plug the outlet and wash
Fit a bung in the outlet so no water or product gets inside. Wet the silencer with a sponge, apply WD-40 Multi-Use to greasy spots and carbon, leave it a few minutes, then wash off with warm soapy water. Treat very dirty areas again. Rinse and dry with microfibre.
Step 3
Go over it with steel wool
Wet the surface again and rub with 000 steel wool. To save effort, use a drill with a soft finishing brush. Sand stubborn marks with wet P1000 paper. Never sand dry, or you will leave scratches.
Step 4
Remove rust
On rust-pitted areas, work from coarse to fine: wet P180, wipe and check the result, then P280, then P500. Finish with P1000 and steel wool. Rinse the slurry off with water after each stage.
Step 5
Polish
Dry the silencer, apply metal polish and let it haze over. Then buff with a clean microfibre cloth to an even shine.
Step 6
Protect and refit
Apply a thin coat of WD-40 Smart Straw to the outer surface and the fixing threads and buff with microfibre: it displaces moisture and holds back fresh corrosion. Always wipe off the excess, as it will smoke on the first warm-up. Remove the bung and refit the silencer, tightening the clamp and bolts.
Tip: Cleaning the inside only makes sense with the silencer removed: internal carbon is cleared with dedicated brushes, and the part must be dried thoroughly before refitting. If your silencer is carbon fibre, wash it only with a soft sponge and soapy water.
What next
Repeat the simple wash-and-protect routine every few weeks in season and always before winter storage. For the headers near the engine, see our separate guide to cleaning a motorcycle exhaust manifold.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
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