Andy ,When I fitted Hyde silencers to my Bonnie , they came with jets .I think if you are fitting anything other than standard silencers then you will have to do the same .I suggest a call to Norman Hyde or Mototwin to clarify .For the sake of a couple of quid on jets and an afternoon of fiddling ,I wouldn't chance just dropping them on.
They will make a nice noise

,I could not go back to standard pipes after running mine on the Hyde jobbies .
Rob .