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?

 

Seems to be the same regardless of fuel level. To myself who knows absolutely nothing about bike mechanics the only way to describe it would be fuel starvation exactly like when you have to switch the tap to reserve.

 

The feeling of fuel starvation is exactly what you would have with a blocked vent, it's worth a check.

 

Of course I will check, I’ll investigate any possibility’s suggested.
Thank you very much for your help 👍

 

When it starts to splutter, just pop the filler cap open, can you hear air being sucked in / does it start running better. If so then as suggested above the vent is blocked.

 

Thank you, I’m going to give it a run tomorrow and make it happen again and will try it. Thank you guys for your input.