A motocross bike comes back from every ride covered in mud, sand and water, and its reliability and your safety depend on how you care for it. Dirt holds moisture against the metal, clogs the air filter and turns chain lube into an abrasive paste.
Routine care is done after every ride, and deeper servicing by engine hours according to the manufacturer's manual. Here is the basic sequence for both two-stroke and four-stroke bikes.
What you will need
Important: Keep all lubricants and
WD-40 Multi-Use off brake discs, pads and tyres. Clean brakes only with a product made for them. Wash the bike with a cold engine and never aim the pressure washer directly at the air filter, bearings, seals or electronics.
Step 1
Wash the bike
Put the bike on a stand in a well-ventilated area. Before washing, plug the air filter intake and the exhaust. Rinse off the heavy mud, treat very dirty areas of the engine and frame with WD-40 Specialist Degreaser, scrub with a brush or sponge and rinse. Dry the bike with a cloth or compressed air.
Step 2
Drive out moisture
After washing, water sits in the engine fins and on cables, bolts and connectors. Treat these areas with WD-40 Multi-Use: it displaces water and protects the metal from rust. Spray any wet wiring connectors with WD-40 Specialist Contact Cleaner, which evaporates without residue. Cover the brake discs with a rag.
Step 3
Clean the brake discs
Wipe the brake discs with a dedicated brake cleaner or isopropyl alcohol on a clean rag to remove dirt film and any stray lube. Hold a basin underneath so the cleaner does not run onto the tyre.
Step 4
Clean the chain
With the engine off, apply WD-40 Specialist Degreaser to the chain while turning the rear wheel by hand. Scrub if needed and wipe the chain dry. Do not use stiff wire brushes on O-ring or X-ring chains, as they damage the seals.
Step 5
Check the wear parts
Inspect tyres and pressures, spoke tension, brake pads, sprockets and chain tension, and the tightness of the main bolts. Clean or replace the air filter: on a motocross bike this is needed after every ride. Check the fork seals for oil traces.
Step 6
Lube the chain
Apply WD-40 Specialist Motorcycle Chain Lube to the inside of the clean, dry chain while slowly turning the wheel. Let it set for a few minutes and wipe off the excess so sand does not stick to it.
Step 7
Plan servicing by engine hours
Do deeper servicing every 10-50 engine hours as the manufacturer's manual specifies: engine and gearbox oil changes, brake fluid, spark plug, clutch, shock, forks, swingarm, hoses, battery and fuel system checks.
Tip: Keep a log of engine hours and work done in your phone notes. You will never miss an oil or filter change, and when you sell the bike the log gives the buyer confidence.
What next
Wash, dry and look after the chain after every ride, especially after a wet track. Before an off-season break, see also our guide on storing a motorcycle over winter.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».