NC50 Express and PA50II Hobbit use automatic oil injection — oil in a separate tank, pump meters into the intake. From the Honda Express guide: when it works it’s brilliant; when it doesn’t, you seize fast. These are still two-strokes — they are not “just dump oil in the gas like a Maxi” bikes on stock injection.

Failure modes (from the Express guide)

  • Disconnected or stuck pump cable = riding on straight gas.
  • Old oil lines collapse internally — replace and verify flow into the carb boot.
  • Bikes that sat for years: clean the oil tank; don’t only top off stale oil.
  • Some smoke on startup is normal; billowing blue after warm-up suggests over-oiling / stuck pump.

Checklist before you ride or buy

  1. Oil tank clean and filled with the correct two-stroke oil for injection systems (per your manual).
  2. Cable free and adjusted so the pump moves with throttle.
  3. Lines soft but not collapsed; flow visible into the intake / carb boot when commanded.
  4. Always verify oil pump operation before paying “low miles” money.

Buying / compression note

Compare compression to a known runner; roughly below ~90 PSI warm warrants top-end inspection per the guide — still not a universal law. Compression alone lies if the pump is dead.

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