Mysterious misfire

[taksi]

I ride a '58 plate FZ1 Fazer and have had it for around 18 months during which it has beeen faultless. Last Tuesday, however, I went into town and found it had developed a weird misfire. When moving from a standing start or when filtering on a closed throttle, then opening up there was a severe miss as the engine virtually stopped then picked up, then stopped  and picked up again before flying off up the road. Disconcerting! If the revs are anything over closed throttle (ie 1800rpm) there is no problem. Had the fairings and tank off to see if a connector was making/breaking, especially the throttle position sensor, vac pipe adrift etc but couldn't see anything so opened them up sprayed with WD and reconnected all the ones I could see (except ECU) and went for a ride. Got to the end of the street, still the same. BTW plugs changed about 2k ago. Any ideas gratefully received before it goes to Mr Yamaha and my wallet takes a beating. No fault codes on the dash either. Baffled!


Ta very much in anticipation.



Taksi


Taksi