Hello everyone...I'm Ben and live in Portland Oregon. I've installed 2 gubbee 48cc 2 stroke centrifugal pullstart engines on mine and my girlfriends schwin mountain bikes in three days. And almost loved every minute. Lol but now I don't think the 48cc is going to cut it. We have many grades and the engines just don't have the power to climb most of them. I'm thinking of going with the 80cc but not sure. Anyway Thanks