I just bought the yoshimura rs3 bolt on exhaust for my 06 zzr600. The whole thing took just minutes to put on, but when i tried putting the flange on the rear end of the pipe the threads didn't match up. So for the last week i have been running the bike without the exhaust flange. Now is that going to hurt the bike, or is it just fine running the bike without the flange?

 

I would call up yoshimura for that question. The end cap that I am thinking of is for structural support and without that, the can will vibrate itself loose.

Welcome to KF, good luck