didn't know that you had had further problems
Its a pity about that , it would have been good to try and find the cause as you did have it running really well not so long back.
looking forward to following your engine build

30mm carb sounds a little oversize from what I've been reading recently . Might be worth doing a little more research on that . There is an excellent article about the research Mark at MB Developments did on carb sizing and both Graham A Bell and the Vizard the Wizard recommend smaller venturis for better power for the 200cc .
http://www.mbdevelopments.co.uk/lambretta/lt10.html