Peter
I believe what you call the adapter is the outer race of
the needle bearing if you go for a B & C starter you will need to pull
this bearing out completely & press in a plug which is effectively the
outer race with a sealing cap supplied with the starter kit to seal oil
port.
Ray fitted a B & C starter to reduce weight in his HD but also the sprag
clutch in the original starter was not very reliable as they wear out &
I believe are expensive to replace.
Clive Richards
Rays G CBDG 601HD 265 Hrs
