I own a 1980 Sportster, is a good bike, but I wanted to get more speed on the top end without loosing anything on the bottom end. I wondered about changing out the transm. sprockrt from 21 teeth to 23 teeth, and the rear wheel sprocket from 51 teeth to 48 teeth. Can anybody tell me if I will still have good low end, or is there anything else I should consider. Thanks, tarupert@aol.com