mnostl32

So I just bought my Yamaha VStar 650 classic. Rode on it for a while and decided to upgrade the exhaust. Went to a place where the guy is very knowledgeable and lots of friends recommended this place. Well I bought a set of vance and hines exhaust pipes for the bike. They sound great. When I give it gas it goes fine, when I let go of the gas is when it starts to backfire. I've heard that jetting should be adjusted after upgrading the exhaust pipes and that it doesn't. I haven't jetted since I put the pipes on. I haven't called the guy either. I will though in the morning. This backfiring has been going on for about 2 weeks now. Just curious if anyone has any tips on this. Haven't done a search yet on here but any advice is welcome. Thanks Joe