I just picked up a good condition 1985 XR350 rolling chassis. Now I need an engine. At this time I'm considering three options, and would like comments. This is just going to be a play bike. No serious trail riding or racing of any kind. This project will be on a seriously tight budget. Less then $500, I hope. Option one: Buy one of those Chinese 200cc replica engines and retro fit it. They come with carb, electronics, every thing needed, etc. I am mechanicaly inclined, and have access to a well equipped shop for any machining required for motor mounts, etc. Option two: Install a 1975 XL350 engine that I currently have three of. A quick look tells me that the motor will bolt right in, but I could be wrong. But, will need a carb, electronics, exhaust, etc. Cost would probably exceed option one. Option three: Try to find a 1985 XR/XL350 engine with carb and electronics, but I'm sure this would be the most expensive option. Anyone done any of the above?