will a 125 engine go on a honda 70 frame?

 

Oh alright, since no one else will I shall

Take a mesurement or two, size them up visually, throw the engine at the frame and see what happens

 

Nope!!!!! 90, 110 yes! 125 has a totally different setup. Frame under the motor for instance. angled different#2. unless u want to do some major frame mods aint gonna happen

 

Depends what 125 motor you're talking about. It is possible to fit a motor out of a 125m but it is heaps of work, i have a couple of links below
Link 1
Link 2

on the other hand if it's a 125 chinese motor (crf copy) there are no real issues and has been done many times before