I have mounted a HuaSheng 49cc engine on a Staton friction drive. I removed a Honda 35cc 4-cycle from this bike and replaced it with the HS. This bike has a 1.125 dia drive roller. The extra power of the HS is very noticeable and enough that I won't be going back to the smaller Honda. It handles the hills very well and is quiet and smooth running. I was going to put the HuaSheng on a new bike using the Grubee center mount kit but have since decided to keep it on the friction drive and eliminate the extra 20# of parts required by the center mount.