I really want to start a new thorough project, but my idea would be to start with the engine of an r80 and then add pieces as I needed them as I intend for it to be a very custom project, does anyone think this is a good idea or just an expensive way to go about doing it? For example after rebuilding the engine mounting it on a frame then maybe adding a gsxr front end?

You pays yer money... In general, builidng any custom project is not cheap and you will never get your money back if you sell the end product. In some ways starting with a complete bike is a better bet, if only because you can sell the unwanted bits on ebay.

My current project is disguising a 1993 Moto Guzzi 1100ie California to look like a 1972 Moto Guzzi T3-California. I started with a complete bike but I still had to source an awful lot of parts and make others. Originally I was going to leave the 1100 engine as standard, but that idea's changed. 

Lastly, if it's going to be roadworthy, you will need a copy of the MSVA rules because what you are proposing to create is an entirely new vehicle, unlike the K conversion.

Really, only you can make that choice.

Interesting to know how it all ended

It's your money.
you're free to spend it in creating a custom bike.
Just don't forget that you'll never sell it once it's modified, not because you'll be in love with it but because no one will buy it at any price.

jbt wrote:It's your money.
you're free to spend it in creating a custom bike.
Just don't forget that you'll never sell it once it's modified, not because you'll be in love with it but because no one will buy it at any price.

The only K cafe project I have witnessed involved a young guy with a K75RT.  He looped the frame, but couldn't seem to get the ECU to work after chopping up the harness.  He gave up trying to get it running and abandoned it without ever getting any of the cafe stuff done.  Last I saw it, it was a frame and engine sitting under a pile of dirt in the corner of a heavy equipment garage. 

From time to time unfinished cafe "projects" come up on Craig's List with photos of a frame without a seat or bodywork leaning up against a fence or wall surrounded by weeds and trash.