Registered Forum User
WSB Hero
Bikes: 1993 - 944SS & Aprilia Falco
Posts: 7,795
Join Date: Oct 2002
Location: north east
Working on the 'hiss' and loss of power descriptions I'd be looking around:
loose cylinder bolts
loose carb mountings
loose exhaust rings
as a starter.
I'm sure Nelly / someone much more knowledgeable will be along shortly!
Good Luck - Frank