I have an FZ1 2006 with only 2500 miles which will coughs and backfires when running. At first the engine would cough occasionally then be ok. This has got more and more frequent and now will hardly run at all and kangeroos along the road. The bike has had diagnostic run by a garage but apparently the result was that everything is ok. The bike runs ok at tickover and revs ok but as soon as the engine is under load, that is when the problem starts.
I was wondering if it could be a problem with the air induction system. There are two rubber hoses from the rocker cover which connect to the "AIR CUT VALVE ASSY" (name taken from the yamaha microfiche) and another hose goes from there to, presumably, the airbox. Does this control the flow of air to the cylinders? There are two wires from this valve which go to a connector block under the headstock, these two wire were cut by mistake but reconnected with spade connectors. Could the cutting of these wires be creating the problem described above?
Any help at all would be appreciated.