Altough a petrol engine is cheap enought, Palawan tricycles would be more fun with a diesel engine. Maybe that 400cc single-cylinder Kubota used in tricycles in India could be a good match...

Replaced the turbo of an Isuzu Crosswind this afternoon. Throwing a twin-scroll with ceramic-coated hot carcass into something so old-school as the Crosswind might sound weird, but it reduced the visible smoke belching measured thru a Ringelmann chart at any RPM range, even before the injection pump tuning that followed it.