I had a 74 Z1 (Fastest Production Bike at that time) for a while but I found a Rickman CR chassis with a ATP turbo 1015 Kawasaki engine. The Rickman was a great bike but it required a lot of maintenance. I got tired of working on the motor more than riding. I purchased a 81 Suzuki GS 1100 which was the fastest production motorcycle at that time. The GS 1100 had a lot of torque even at low rpm and it returned gas mileage in the 40 to 50 mpg range. It was the best motorcycle I have ever owned.