The PHBH is possibly the most underrated carb for Lambretta & Vespa scooters, repeatedly overlooked in favour of more ‘exotic’ setups. Yet the PHBH is affordable, available, easy to setup, and has a great balance of cost vs performance vs fuel economy. It’s the CBR600 of carburettors... a brilliant allrounder! Plus, for the vast majority of scooter owners, there are some very repeatable ‘base settings’ which you can use, for around 90% of all scooters, in order to get your ballpark starting point to work from and go on to perform plug chops with. There are also some crucial mistakes you must not make, as these can kill an engine very quickly if not followed.