Hi.
can anyone help diagnose an intermittent fault my cbr600f3 has developed. Runs fine on small journeys at low speed. If on a duel carriageway/motorway when riding at a reasonably consistent speed ! It runs for a short while at this speed but then starts to splutter and really struggles to run when I open the throttle even a little bit. The only way to describe is as if running out of fuel. If I continue to limp it on with very little throttle action (40mph max) it goes back to its normal responsive self. If I give it some constant speed again, the problem repeats. My local garages are unable to help with this. Can anyone help please
thank you 🙏

 

Sounds like a blocked fuel tank vent - is it worse when the tank is full?