Negative on the chain. I've run 16, 17, and 18 with the same rear and chain. my next move will be a 7 with the bigger rear.

2002 Bandit 1200/ GSXR cams/ 1277 BB Kit/ Holeshot header and can/ 38mm flatslides/ a good head/lotsa hp/lotsa tq- lots of rear tires...