I have a 79 Bonneville Special and I believe there must be something missing from the clutch adjustment at the lever. I´ve got the thumb nut adjuster that has the ´V´ in it that should keep it from spinning but there is no corresponding ´V´ shaped area. When I ride, the clutch goes out of adjustment. What i have is the cable, the adjusting nut and then the lever housing. Is there a part missing or should I file a ´V´ groove in the lever housing? Thanks! Buddy