Motorcycle Repair: starting trouble, battery breaker, battery cables

Question
Hi
My HD FLH 1972 1200 cc is about to get me mad !! :)
It wont start. When i push the button it keps turning the starter although the button is released ! I changed the solonoid to a new - it made no difference . The starter relay is brand new . When the button is activated the starter turns realy realy slow - not enough to give rpm s enough for a fire on the plugs. I tried to connect the battery from my car with starting cables , and it was all the same :)Same slow rpm `s at the starter .  
What the heck is wrong with it ? Is it the starter itself ?
kind regards
Carsten

Answer
First, I would test the battery. You might have a bad cell. Check both battery cables. the starter will drag with a bad ground or bad positive cable. Last, check the breaker to the starter. It might be weak. If the battery, breaker and cables check out then your going to have to pull the starter and either rebuild it or buy a new one.
Good luck and happy riding
Mike