[SemiFast]

Wow! That's going to be quite a project.
I'd recommend bailing on it before you start, but that's not what you asked so...
Get the 17 digit V.I.N. off the steering neck and call a dealer that sells the same make as the bike.
(Looks like a Suzuki motor to me).

 

[SemiFast]

That's a Lifan Chinese made engine. Probably about a 250 cc size. I have no idea who made the bike. Maybe an old Honda Rebel with a replacement engine in it?

Ohhhh, In that case .... BAIL before it's to late.

 

[SemiFast]

I believe you're right Dod. You can see where the air filter is missing in the first pic.

The front wheel looks the same to. The fuel tank is kinda, off though....