Re: Might try to build a 125cc Lifan bike
I have experience with the engines, but not in a bicycle frame. I have seen some builds on here using the Honda clone horizontal engines, though.
Here's a tip that might help, though: I would forget the 125cc and up engines because they are wider (bigger clutch pack) and longer (because of the longer stroke) than the true Honda clones. Most of the 110cc and smaller are true Honda clones with the same exterior dimensions as a 50-70cc Honda. They have quite a bit of parts commonality with Hondas, too.