Do carbs need rejetting after fitting a K&N air filter?

[kawasutra]

Free?
I wish..... :\

You should notice the bike breathing more freely with a K&N, so once it's in i doubt you'll even consider a dyno anyway. 

http://pdq1.com/services/



Aah, PDQ! Have had previous bikes on their dyno in the past.

Now, a filter from K&N directly costs 40 quid plus VAT and maybe shipping, but flea-bay seems to have them for  ~£30. Puzzling. Anyone shed some light on this discrepancy??