Whoa, you must be running way too rich! I think I got about 50 to 60 mpg or so with mine back in the late 70´s. My best run was against a 250 motocross bike on a logging trail in the woods. I kept having to slow down for the mud puddles on the curves (those street tires got no bite in the mud!). He challenged me to a drag when we got to the highway, him on the shoulder me on the blacktop, and I left him in the dust right from the starting line. Mine would top out at about 91 mph no matter how tight I hugged the tank. But, then again, it would be wobbling so badly by then that I wouldn´t want to go faster. It took work to keep the front tire down on a fast start. You should be getting this kind of performance. As far as I can tell, it had an engine similar to that of the present day Banshee in a very light street bike (hmmm, maybe you could find a Banshee engine and do a little swap).