The carburettor off the 348 runs rich, unsurprisingly after thirty years it's rather worn. The main problem is the slide which gets pulled against the inlet tract. Eventually the cylindrical face wears with a notch and easing it down with a file smooths the movement but leaves it even looser. Apparently the bore wears at the same rate so replacing the slide is pointless. Time for a new carb. Except I want to keep this on the bike and make it last just a bit longer. So last night I sat down at the kitchen table, pulled it apart and ordered a 140 main jet (down from 150) from Amal. At £3 it's a cheap solution. I'll post if it works, or not.