Great advice John! By the way the 1984 factory manual for ETZ 250 describes a silencer tube that goes into the oblong hollow of the frame under the fuel tank and connects somehow with the air box. It might not be an essential element and no reference is given to it in the Haynes manual. Do you know if this an actual pipe/tube that runs through the frame or just a way of describing the route of air into the air box before it is drawn into the carburettor? Hopefully this makes sense, and once again I appreciate everyone’s advices.