The hitachi starters ive seen on 1200's do strip down well. the cap on the solenoid screws off so you can acsess the contacts to either clean or replace. check the brushes and bushes as "tapping the starter" to get it going can also be due to "poling" (that dont look right). Just be carefull when cleaning the commutator and dont use normal sandpaper....either glass paper or a scourer is the go..
good luck