Until electric cars and their associated technologies (motors, batteries, controllers etc.) become mainstream, the internal combustion engine will need to be further refined in order to meet upcoming fuel economy requirements and current emissions regulations -- while still producing the power that consumers have come to expect. HCCI is one technology currently being developed to make these goals possible, while direct injection and turbocharging are simply becoming quite common.
A few years ago, Bajaj stopped making their Chetak and Legend scooters, and since then there has been a dinstinct lack of any steel-bodied, manual transmission, 4-stroke scooters on the market. Genuine Scooters has begun selling their Stella scooter again after a short absence and Vespa themselves re-released 500 of the PX150 model to the American market, but both of those machines feature 2-stroke engines. Bajaj made some pretty compelling claims regarding the emissions improvement of their 4-s