AI DamageYamaha YP400: problems, complaints, bulletins
Summary for the Yamaha YP400 across 5 model years: 13 owner complaints and 0 NHTSA service bulletins, plus repair videos. Pick a year for details.
Model years
What fails most often
- 1 Electrical system 31% of all complaints
- 2 Engine and cooling 31% of all complaints
- 3 Fuel system 23% of all complaints
- 4 Fuel/propulsion system 15% of all complaints
- 5 Engine 8% of all complaints
- 6 Vehicle speed control 8% of all complaints
- Electrical system: 4 complaints (31% of all).
- Engine and cooling: 4 complaints (31% of all).
- Fuel system: 3 complaints (23% of all).
- Fuel/propulsion system: 2 complaints (15% of all).
- Engine: 1 complaints (8% of all).
Symptoms owners describe
How many of the 13 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Electrical system | 4 | 0 | 0 |
| Engine and cooling | 4 | 0 | 0 |
| Fuel system | 3 | 0 | 0 |
| Fuel/propulsion system | 2 | 0 | 0 |
| Engine | 1 | 0 | 0 |
| Vehicle speed control | 1 | 0 | 0 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
Turn signals- when using the left signal, the right front signal flashes and the rear left signal flashes. When using the right signal, the left front signal flashes and the right rear signal flashes. This happens at all times.
Then engine had issues restarting again so I had the bike picked up by a dealer near me and after inspection I was informed that it was a bad fuel pump, and that there are a lot of post in the web of similar occurrences to other owners of yamaha majesty 400's.
In hot weather, the yamaha yp400 fails to start, stalls at idle, and intermittently cuts fuel at high speed. Symptoms are nonexistent until the air temperature exceeds about 95 degrees f.
Once engine was warmed up, vehicle stalled at stoplights twice and once when starting to move after a stop (when in an intersection). Other times when stopped. Idle speed dropped below 1400, under which it stalls, and it was difficult to rev the engine to prevent stalling since there is no neutral gear, so revving…
The contact stated that while driving 10 mph, the scooter stalled without any prior warnings. As a consequence his risk for serious injury and crash were increased. The scooter was taken to a dealership in which a technician concluded that the fuel injector was the cause of the failure.
The vehicle was repaired according to nhtsa campaign id number 08v180000 (fuel system, gasoline:delivery:fuel pump); however, it continues to stall and shut off. The contact feels that the actual harness was not replaced according to the remedy, and was only inspected at the time of the repair.
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
What to check before buying
- Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
- Engine and cooling. Radiator and fan after a frontal hit, coolant level and condition, overheating.
- Fuel system. Fuel smell, leaks, rough running, fuel-system codes.
- Fuel/propulsion system. Fuel smell, leaks, rough running, fuel-system codes.
Other models of this make
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-06.