Stig,
Did you over fill the tank at all? I'm wondering if the evap canister is filled with fuel. This can cause sporadic performance.
Have no idea....think not. Did change out valve snd lines from the fuel neck vent.
SYM folks rip out the whole evap/tree~hugger system....I'd like to do that.
Checked more grounds today, retightened intake breather fittings, checked.exhaust bolts, replaced reg NGK with iridium because of its ability to fire under less than ideal conditions.
Refitted and tightened injector, and plug wire to coil.
Beginning to think something quit working rather than something came loose.
Injector, ECU, coil, ....? Still no celp fault codes.
Will try calling the Vespa/Aprilia dealer for service.
Stig