| My 03 749s did exactly the same ... and still does once in a blue moon.
Had the CO2 adjusted at 600 mile service when the race can went on and it cured it, well almost. Going back in for it's next service and will get them to see if the can sort it 100%.
Agree with the comments about using the "choke". Full lock turns will make the engine race if you've got the "choke" on. |