(Posted on behalf of Lisa H) ...... I have a 1958 BSA B31 and the rocker arms on mine, the exhaust rocker has 2 oil holes on each end? The inlet rocker only has 1 hole - is this correct ?
I cannot reply precisely but my DBD rocker feeds have different oil hole sizes.
The exhaust feed is large diameter and inlet is smaller so that suggests the B series might have two holes on exhaust and smaller on inlet for presumably greater cooling effect, but, considering that the top end gets its lubrication from hot oil in the return line the effects must be minimal.
I never noticed that before, but yes. Just checked my parts box and all the exhaust rockers have 2 holes while the inlet has only one, at the pushrod end.
Thanks .. I will pass it on