Personally I always run my Bonnie on BP Super as it's E5 and allegedly contains no ethanol, I have no choice with my Guzzi as that runs like a sick dog on ordinary petrol despite the fact it's supposed to be compatible with E10. It could be worth checking your valve clearances (or getting them checked), a bloke I know has a similar problem on his Bonnie and it only appeared after a local back street bike shop had done his valve clearances. He's pretty sure the shop have set them wrong but they're denying it
E5 = Up to 5% according to Esso's web site, which says: Although our pumps have E5 labels on them, our Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, North Wales, North England and Scotland). Legislation requires us to place these E5 labels on pumps that dispense unleaded petrol with ‘up to 5% ethanol’, including those that contain no ethanol, which is why we display them on our Synergy Supreme+ 99 pumps.
