I’d had the stink of fuel for a while but couldn’t find the leak until a week ago when i found fuel gushing out of the return pipe just under the front of the tank. When i stripped the bike i found the hose badly degraded with many cracks no doubt caused by the ethanol fuel. Now guzzis replacement hose costs £57 
, a trip to a local shop got me one made up with the old fittings for a tenner–result !. I cannot belive the difference it has made to the running of the bike, the hose must have been allowing a reduced fuel presure for a while which was affecting the smooth running of the engine . If you have a cali this old check this hose if only from a safety point of veiw.
John