I have a 660z that is cutting out on me with some regularity. Seems to be happening after the engine is up to temp. The engine light does come on. I can then start the bike after 30ish seconds. The light is not intermittent, but the issue is if I leave the bike for 5 mins it will start again, making trouble shooting hard. It stays on for a bit of hard riding, then dies again.

I am thinking start by looking at the side stand switch, then wiring loom, then checking the resistance across the solenoid? Any more seasoned people got tips? Any yamaha mechanics? I want a clear plan of action before removing things; I might not then be able to easily reproduce the issue...

I changed the question in the thread and decided to bump it

Electric gremlins love playing hide and seek. The F1 diag tool would give you the fault code but without that I would respectfully suggest that a check is made of the wiring loom under the tank, where it's known to rub on the frame. Also check the rectifier connection for burnt terminals and elec values. (Another known Gremlin)...I'd check both sides of the coil for visible damage and the plug cap and plug, then measure its elec values/performance too. As you say, the cut-out switches are also cousins in the gremlin family but would not generally flash an ignition warning dash light (but still worth a 'continuity' check)

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