i believe he means the bolt to tighten the oil filter...
can't u find a similar one in bunnings?[hr]
nevermind what i said, i forgot what they looked like. lol
maybe this will fit? http://cgi.ebay.com.au/Honda-CB350F-F1-Oil-Filter-Centre-Bolt-Nos-NEW-/300330378606?cmd=ViewItem&pt=AU_Motorcycle_Parts_Accessories&hash=item45ed15e56e[hr]
or this..
http://cgi.ebay.com.au/NEW-Honda-oil-filter-bolt-CB250N-CB400N-CX500-GL500-CX6-/390215982015?cmd=ViewItem&pt=UK_Motorcycle_Parts&hash=item5adaaf5bbf
or
http://cgi.ebay.com.au/NEW-Honda-oil-filter-bolt-CB400F-CB500F-CB550-CB750-CB9-/370404763288?cmd=ViewItem&pt=UK_Motorcycle_Parts&hash=item563dd82698