I use my F1 daily and can confirm I see no fuel problems at all. She gets a bit sulky if left for more than a weekend though, always starts but runs on 2 for a bit. Unsure if this is the fuel itself or whether I have a blocked drain tube or similar so 2 carbs are not filling as quickly as they should, I say this as if I turn the fuel on a few minutes before starting shes a bit better.