Got this to run my '74 225cc Lambretta. Fought with it for days trying to get the jetting set up. What was really happening was fuel starvation! The main one above the float valve was drilled off centre causing fuel starvation. Every fuel passage needs to be drilled out. (You will need a 1mm, 2mm, 2.5mm and a 5mm if you wanna try.) Also the top cable guide kept coming loose and falling into the carb body. Ended up putting a dab of solder on it to keep it in place. In the end I did get it working good but maybe try a Polini PWK or the Mikuni TM24 and save yourself some headache.