Ive been chasing this problem for over a year and unable to ride the bike. Early 1974 R90/6 with 125k miles. What i want to do is to check the grounds as its been recommended to me that might be a problem. I need to know where/what to check on the bike for grounds other than the obvious place at the battery....below I will explain how i got to here Bike started getting a slight miss at constant speed/throttle noticeable at 45-50 mph plus. At constant speed you will feel it lose power slightly, several times a second sometimes and the front of the bike will drop slightly. I can ride it at neighborhood speeds with no problem. starts and idles fine. So far I have: reset points resynced carbs readjusted valves changed plugs swapped out coils (for others I have on the shelf) swapped out plug wires (for others I have on the shelf) carbs removed, cleaned, tore down, inspected, checked for leaks retimed with timing light replaced points/condenser (I feel like im forgetting some items here and will edit them in as I remember) replaced fuel filters Gas tank inspected, flow tested dumped fuel, fresh gas, then upped to 94 octane neg battery cable replaced and mounts to the engine, not frame Compression test shows 150 left 120 right, added oil to right side, retested only increased to 125 grounds are easier to check, next up will be pulling the front off the motor and checking/replacing the timing set (chain/gears).