bikebandit jet sizes

wondering if someone know the difference between the jets found on Bikebandit

my manual tells me i have a primary jet #65

what would be the next step up? and..

would it be a good thing to bump up the main jet one size if i used a k&n filter in the stock airbox?

the bike ran a little lean before but i think that was at least partially caused by a vacume leak

perhaps ill just put it back together and see how she does b4 i go changing things

suggestions?

I don't think you have to jet up just from changing the air filter type.

I recall Kawi jets step up in size increments of 2.5 or 5.