The 660 I believe has a Minarelli engine, or it did at one time.
http://i784.photobucket.com/albums/y...2b0d5cdcd2.jpg
Here is another suggestion for them from Oberdan....also uses the 660cc Yahmaha Minarelli.
http://i784.photobucket.com/albums/y...82accc1ce2.jpg
I am surprised that they can still make the two-stroke these days?