I have a 1954 servi. Having speedo problem. New2:1 speedo , new cable, new drive gear (8 tooth) ring gear(20 tooth) looks good no sharp teeth, ect. PROBLEM: works fine forward, roll reverse 6" strips teeth off drive gear. Have ruined 3 drives. Any thoughts?
Sounds like your drive gear in the rear end is off center. Rolling forward there is plenty of leeway for gear lash, in reverse it is binding on the cable drive and stripping the teeth. The drive ring need to be centered and locked into position.