EXHAUSTING ISSUES
The Lambretta exhaust system is a simple two-piece design compromising the downpipe and box section, so why is it so difficult to stop it coming loose? There are various reasons forth is and none more so than the way Innocenti made it in the first place. It is vitally important for the exhaust to remain airtight to prevent the spent gases escaping from anywhere else than the end of the tailpipe. The problem is if it does come loose then running issues occur and quite often that's exactly what happens.
Downpipe
Starting at the engine end, you have a downpipe that sits flush against the cylinder. There is no recess for the pipe to sit into, just two small 7mm studs to hold it flat against the surface. In between sits a small copper gasket to create the perfect seal. If one of the nuts securing it in place does come loose, gas will escape from this area. This is instantly recognisable as the engine will run erratically at low revs and it will be impossible to set a correct tick over. It doesn't help that the exhaust port faces the floor, which seriously hampers the ground clearance.
A point
