Buying a used liquid-cooled bike: what to check

What you need

• A torch, a clean rag, and a friend or mechanic who knows bikes
• Your licence and helmet for the test ride

Steps

1. Ask for the papers before you even look at the bike: the BRTA registration certificate (smart card, or the older blue book), the tax token, the insurance paper and the seller's NID. Motorcycles do not need a fitness certificate, so that is not one to look for.
2. Match the name on the registration to the seller's NID. If the bike is in someone else's name, the registered owner must sign the ownership transfer with you. Without that signature BRTA will not move the bike into your name.
3. Read the chassis number (stamped on the frame, usually near the steering head) and the engine number (on the engine case). Both must match the registration exactly. Filed, re-stamped, painted-over or uneven digits are a reason to walk away.
4. The number plate should be the BRTA-issued digital (retro-reflective) plate with the same number as the papers. A hand-made or mismatched plate needs a clear explanation.
5. Check the tax token's expiry date. If it has lapsed, the arrears and fines usually land on whoever owns the bike next, so agree who pays before any money changes hands.
6. Ask whether the bike has pending traffic cases or e-fines, and check yourself on the official online service before paying (our e-fines guide shows how). Unpaid cases follow the bike.
7. Write a sale receipt with both NID numbers, the date, the price and the chassis and engine numbers, signed by both of you. Then do the ownership transfer at BRTA soon. Until it is done, the bike legally stays in the seller's name.
8. Before starting, with the engine cold: the coolant in the reservoir should sit between the low and full marks. Never open the radiator cap on a warm engine.
9. Look at the coolant colour. Proper coolant is clear and coloured, often green, blue or pink. Rusty brown, cloudy or plain water are warnings. Many used bikes run on tap water, which leaves scale and lets the inside corrode; mixing different coolant types is not recommended either.
10. An oily film or bubbles in the coolant, or milky oil in the sight glass, can mean a failed head gasket letting oil and coolant mix. Steady white smoke with a sweet smell that does not clear once warm points the same way.
11. Ask the seller not to start or ride the bike before you arrive, and touch the engine when you get there. It should be cold. A warm engine hides hard starting, smoke and noises.
12. Start it and watch the exhaust, then rev it a few times. Thin white vapour on a cool morning that clears in a minute is normal. Blue or grey smoke means it is burning oil (worn rings or valve seals). Black smoke means it is running too rich.
13. Listen at idle and as it warms. A light, even ticking is normal. Loud tapping from the top, knocking from the bottom, a rattle for the first seconds after start-up, or grinding are not. Look for oil seeping around the cylinder head and the base of the cylinder.
14. Hard starting together with weak pulling and blue smoke points to a tired top end (low compression). A mechanic can measure compression with a gauge in a few minutes.
15. Radiator and hoses: look for bent or blocked fins, leaks or green or white crust at the hose joints and the cap, and hoses that feel hard, cracked or swollen. A replaced or bent radiator on a faired bike like the R15 or RC 125 is also a fall clue.
16. Water pump: find the small weep hole under the pump on the engine case. Dried coolant trails or drips there mean the pump seal is going.
17. These bikes are fuel-injected too: the FI light should come on briefly at key-on and go out after starting, and it should start without fuss when cold. The air-cooled FI guide has the full list.
18. Fan test after the test ride: let it idle until it gets hot. The fan should switch on by itself and the temperature should come back down. If the fan never runs or the temperature light comes on, do not buy until it is fixed.
19. Ask directly whether it has ever overheated. Discoloured exhaust pipes near the engine, cooked hoses and a coolant level that keeps dropping are signs it has.
20. Clutch slip test: in a high gear at low speed, open the throttle quickly. If the revs jump but the bike barely speeds up, the clutch plates are worn. It should also find neutral easily, and the lever should have a little free play.
21. Chain and sprockets: try to pull the chain backwards off the rear sprocket. If it lifts away and shows a big gap, the chain is stretched. Hooked or pointed teeth mean the chain and both sprockets are due.
22. Accident signs: scraped bar ends, levers, footpegs, mirrors or engine cover; dents in the tank; new panels that do not match the rest; welding or fresh paint on the frame. Stand in front and behind: both wheels should line up, and the handlebar should be straight when the front wheel is.
23. Forks and steering: look at the shiny fork tubes for oil, rust or pitting. Push down on the front a few times; it should rebound smoothly, without clunks. Turn the bar from lock to lock; it should move smoothly, not notchy or loose.
24. Flood damage, common after the monsoon: dried mud or silt where washing does not reach (under the seat, in the air box, around wiring plugs, behind the headlight), green or white crust on connectors, rust on bolts low on the bike, fog or a water line inside the headlight or meter, a musty smell, and milky engine oil.
25. Odometer: do not trust the number alone. Both mechanical and digital meters can be wound back. Compare it with the service book stamps and with wear on the grips, footpeg rubbers, gear lever, brake pedal, seat, tyres and chain. Very low kilometres with worn rubber and a stretched chain do not add up.
26. Test ride with your licence and a helmet on a quiet road. Use every gear up and down, brake firmly once from moderate speed, ride straight with a light grip to feel any pull to one side, and check the horn, lights, indicators, self-start and kick start if fitted.
27. Before paying, have a mechanic you trust look it over, not one the seller brings. If anything above worried you, use it to lower the price or walk away.

Common mistakes

• Jumping at a price far below the usual used price for that model and year. The common reasons are a stolen bike, flood or accident damage, or papers that are missing or cannot be transferred. Be extra careful, or walk away.
• Paying an advance to 'hold' the bike before you have seen the original papers and matched the numbers yourself.
• Buying on 'the papers will come later', or with only a photocopy of the registration.
• Inspecting at night, in the rain or right after a wash. Water hides leaks, and darkness hides dents and smoke.
• Believing 'it only has water in the radiator, that is fine here'. Without coolant's corrosion protection the pump and radiator wear faster; plan to flush and refill it properly.
• Checking the coolant only after the seller has warmed the bike up. The level reads differently hot, and you cannot safely open the cap.

When to go to a mechanic

• Always, before you pay. A short inspection costs far less than buying the wrong bike.
• Blue smoke, knocking, clutch slip or a bike that pulls to one side: get a compression test or frame check and price the repair before you agree.
• Coolant that keeps dropping with no visible leak, or oil in the coolant: get a cooling-system pressure test or head gasket check before you pay, or walk away.

More guides

• Buying a used carburettor bike: what to check
• Buying a used air-cooled fuel-injected bike: what to check
• Buying a used oil-cooled fuel-injected bike: what to check
• Coolant and radiator care (liquid-cooled bikes)
• Monsoon riding and bike care
• What to do after a crash or breakdown