Stock M8 tune with no CAT7 Aug, 2017 in Head Hoggers tagged harley engine kits / harley head porting / harley machine shop / Harley Performance / Head Hoggers / M8 builds / mobile motorcycle tuning by headhoggers Just got this tune done on this 107″M8 bike. Bike is completely stock minus the cat. They gutted it themselfs. Not to bad! The blue is a run as is when they brought it.