How to check a 50cc bike and its papers before buying

Buying a used bike hand-to-hand, it’s easy to end up with a worn-out or stolen one. But 10–15 minutes of checks filters out most problems. Here’s a checklist — papers and mechanics.

1. Papers — the most important

• cà vẹt (registration) — must be in the seller’s hands, legible, not “we’ll sort it later”.
• Matching numbers. Check the số máy (engine number) and số khung (frame number) on the bike against the cà vẹt. If they don’t match (sai số máy) — stolen or tampered, walk away.
• Capacity. The papers must say 50cc — otherwise “no licence” doesn’t apply.

2. Engine and mechanics

• Start it COLD. A seller may warm it up to hide a hard start. Ask for the engine to be cold.
• Listen: runs smoothly, no knocking. Exhaust smoke: blue = burning oil/wear, black = fuel mix issues.
• Test ride: smooth acceleration, brakes (front and rear), suspension, steering tracks straight.
• Electrics: headlight, indicators, brake light, horn, speedo — all working.

3. Condition and mileage

The odometer can be wound back, so judge overall wear: tyres, brakes, worn grips and seat. Look for rust, cracked plastics, crash signs (bent forks, fresh paint, uneven panel gaps).

4. The price trap

A price far below market is almost always a warning: dead engine, hidden loan (trả góp) or stolen. Cheap ≠ lucky.

Don’t want the hassle — buy checked

We do all these checks for the buyer: papers verified against the police database, numbers matched, serviced, with a warranty and a 50% buy-back. You get a clean bike, no surprises. See where to buy and where not to and how buying works with us.

See checked bikes → Where to buy →