Well it is not that simple. I need exact measurements and technical specifications. Even though a 4 stroke engine has more mechanical parts as compared to 2 stroke, it doesn't mean that restoring a 2 stroke bike is any less complex than a 4 stroke say honda CG125. From a mechanical engineer's view point a 4 stroke engine (only engine, not whole bike) might be a bit more overwhelming than 2 stroke. But from a mechanic's point of view (and I hate the word 'mechanic' ) you have to bore the cylinder if needed, replace components, sort out electricals, remove rust and stuff like that. This process is almost identical in both 2 stroke and 4 stroke. There are just a greater number of components (in the engine) to put back together in a 4 stroke. Engine is just one portion of the bike. The electricals, ignition timing and point system of an old 2 stroke can sometime prove to be a nightmare if you don't know what you'r doing.