Motorcycle maintenance you can do at home

Viscosity. Numbers like 10W-40 describe how oil flows cold and hot. Use what the manual lists; 10W-40 and 10W-50 are common.

Use motorcycle oil marked JASO MA or MA2. Most bikes share one oil supply between the engine, transmission and wet clutch. Automotive “energy conserving” oils carry friction modifiers that can make the clutch slip. The JASO MA/MA2 mark means the oil is safe for a wet clutch.

Mineral or synthetic. Factory fills are often mineral or semi-synthetic. Synthetic holds up better to heat and time and costs more. Switching needs no flush or special procedure: drain, refill, done. The exception is break-in, where some manufacturers specify mineral oil for the first service.

Procedure

1. Warm the engine for a few minutes so the oil flows, shut it off and let it sit briefly. Hot oil burns.
2. Stand the bike the way the manual says (sidestand or upright).
3. Remove the drain plug over a pan and let it empty. Some bikes, KTMs especially, have more than one drain plug or an oil screen to clean.
4. Replace the filter. Put a thin film of fresh oil on the new filter’s rubber seal so it seats cleanly.
5. Refit the drain plug with a new crush washer and torque it to spec.
6. Fill slightly under the listed capacity, run the engine for a minute, shut off, wait, then check the level the way the manual describes and top up to the mark.
7. Take the used oil to an auto parts store; many recycle it for free.

An engine is an air pump, so the filter matters. There are three kinds:

• Paper: replace it.
• Foam: common on dual-sports and dirt bikes. Wash in filter cleaner (never gasoline), rinse, dry completely, oil evenly with dedicated filter oil and squeeze out the excess.
• Oiled cotton gauze: clean and re-oil with the manufacturer’s kit.

If you ride dirt roads, ignore the schedule and check often. One dusty weekend can do more to a filter than a thousand miles of pavement.

Getting to the filter is the variable. On many dual-sports it sits under the seat, a few minutes’ work. On many road and adventure bikes it is under the tank, which turns a five-minute job into an hour. Stuff a clean rag in the intake while the filter is out so nothing falls into the engine. Many riders keep a pre-oiled spare foam filter in a zip-top bag for a five-minute trailside swap.

Fuel filters. On most fuel-injected bikes the filter is inside the tank on the pump, with long intervals. It is rarely a routine job and not one to do at home. Older and carbureted bikes may have a visible inline filter that is easy to swap, roughly every 20,000 miles.

Fuel stabilizer. Essential for storage of a month or more, especially with ethanol fuel, which breaks down into varnish.

1. Fill the tank nearly full, leaving less air to oxidize the fuel.
2. Add stabilizer at the label’s ratio.
3. Run the engine a few minutes so treated fuel reaches the injectors or carburetor.

Sea Foam. Helps dissolve varnish in carbureted engines: older bikes, small dirt bikes and two-strokes. On a modern fuel-injected bike, with its sealed, pressurized system, it adds little, and it does not replace stabilizer. Don’t add it to the crankcase oil, which also runs the clutch.

The job you will do most. Modern O-ring and X-ring chains seal grease inside each roller, so use a cleaner labeled O-ring safe, or kerosene, with a brush. Never use harsh solvents or a gasoline rag. Scrub, wipe, then lube after a ride while the chain is warm.

Slack. The manual gives a range, how the bike should stand, and where to measure. Too tight is worse than too loose: it hammers the output shaft bearing and rear wheel bearings. Adventure bikes with long suspension travel have a slack spec that looks loose. Trust the manual, not your eye.

Adjusting slack

1. Roll the bike and check slack at several points. Chains wear unevenly; set it at the tightest spot.
2. Loosen the rear axle nut.
3. Turn both adjusters the same amount, using the swingarm alignment marks to keep the wheel straight.
4. Torque the axle nut to spec, then measure again. Tightening the axle can pull slack out of spec.

Pads. Most pads have a wear line or groove, and the manual gives a minimum thickness. Check with a flashlight every few weeks.

Rotors. Rotor cleaner is for contamination (oil, chain lube, brake fluid), not routine washing. Don’t touch rotors with bare fingers.

Fluid. Most bikes use DOT 4, which absorbs moisture and causes corrosion, so the common interval is every two years whether you ride or not. The reservoir cap names the fluid. DOT 3, 4 and 5.1 are glycol-based; DOT 5 is silicone and must never be mixed with them. Glycol fluid strips paint.

Replacing brake fluid

1. Cover painted surfaces. Open the reservoir and pull most of the old fluid out with a syringe. Never let it run dry.
2. Refill with fresh fluid from a sealed bottle.
3. At the caliper, run a clear hose from the bleeder into a catch bottle. Open the bleeder, squeeze the lever, close the bleeder before releasing.
4. Repeat, keeping the reservoir topped up, until the fluid runs clean and bubble-free. Do both front calipers, then the rear.
5. Before riding, the lever must feel firm and consistent. If it is spongy, bleed again or take it to a shop.

Air compresses and fluid does not, so any bubble turns lever travel into squeezed air. Bubbles cling to high points and banjo fittings; tapping the lines helps, and some riders zip-tie the lever to the grip overnight to let small bubbles rise.

At home: wipe the fork tubes clean after dirty rides (microfiber leaves no lint), watch for weeping seals, clear grit from under the seal with a seal cleaning tool, set sag, and use the clickers.

Fork oil degrades and has a service interval, far shorter on dirt bikes. Conventional damper-rod forks are home-serviceable with patience. Cartridge forks and nitrogen-charged rear shocks go to a suspension shop. Nothing in suspension gets “topped off.”

Coolant

Check the overflow tank with the engine cold; the level should sit between the marks. Top up with the same premixed coolant already in the system, and use the type the manual specifies. Motorcycle engines are full of aluminum, and not every car coolant suits them. Never open the radiator cap on a hot engine.

Coolant’s corrosion inhibitors wear out, so it has a replacement interval, often every two to four years. Replacing it means draining, refilling and bleeding out air, because an air pocket creates a hot spot. Wipe up spills; coolant tastes sweet to pets.

Battery

Keep the battery on a tender during storage. A lithium battery needs a tender with a lithium mode.

Tires

Check pressure cold, weekly. It costs nothing and is one of the most important safety checks. Tubeless motorcycle tires are built like car tires and don’t need liquid sealant.

One-time tools

• Click-type torque wrench, 3/8 in (buy this first)
• Socket set, drain pan, funnel, oil filter wrench
• Tire pressure gauge
• Battery tender with lithium mode
• Brake bleed kit and syringe
• Three-sided chain brush
• Fork seal cleaning tool

Consumables to keep on the shelf

• JASO MA/MA2 motorcycle oil, filters, assorted crush washers
• O-ring-safe chain cleaner and chain lube
• Sealed bottle of the brake fluid your cap specifies
• Fuel stabilizer; Sea Foam if you have a carbureted engine
• Foam filter cleaner and filter oil, if your bike uses foam
• Rotor cleaner, microfiber towels, nitrile gloves