Just to clear up one or two points, the JL3 pipes that Cambridge Lambretta supply do fit the Avanti kit, the new bracket type that Andy Francis supplies do not fit as the main bracket is in a different position. Andy does the Franspeed Road & Race pipes to fit the Avanti Kit but must be specified when ordering.
I think Andy may also supply the older type bracket version of the JL3. But again you must specify this. RM
