I dont think based on the information above I would risk spending money on mikuni. (you got to admit its a bit sketchy) what sort of mikuni for a start VM ?TM? suduco? RS? The US site looks a better bet at least there is a carb selected to suit and all the jets and slides sorted is there anywhere like that in UK?
Vincent owners are hard ‘Task Masters’. Trying to answer questions isn’t
good enough, apparently answering the ones not yet asked is also
a requirement.