To cross Swords, motorcyclist went over 100 (6)
I believe the answer is:
bicker
'to cross swords' is the definition.
(thesaurus)
'went over 100' is the wordplay.
'went' becomes 'biker' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'over' is an insertion indicator.
'b00' becomes 'c' ('C' can be a synonym of 'b00').
'biker' going around 'c' is 'BICKER'.
'motorcyclist' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for bicker that I've seen before include "Argue over petty things" , "Squabble" , "Quarrel pettily" , "Quarrel over petty things" , "Quarrel trivially" .)