Well I got a firned who owns a salvage yard for bikes and atvs and snomobiles and I wanted to go find a old Honda 250 or a polaris sport and drop in a street bike engine from like a yamha 900cc ya know for the crotch rockets...How hard would it be? What would be needed? and how mast mgith i be able to go with one of thoses?

 

A lot of research..... Alot.......alot......alot

Then how deep your pocket to do it.

You can do it and take your time.

Good luck