So I bought my bike about a month ago. It would back fire like a champ and it was awesome.

When I put these items on it stopped
-Petcock
-Oil change it was black as hell
-Exhaust sandblasted and painted

Other than that nothing else has changed. I took it on a ride the other day and it did it once or twice. Compared to I can do it whenever I want before I put the new parts on

You either had a fuel leak in your petcock,.. or an air leak in the exhaust..

Now,.. you fixed it...
That's a good thing... ...

Is it bad for the exhaust to back fire I kind of enjoyed shooting flames. I know its bad for an 80s bike because of the starter gear. But only if it backfires when you turn the bike off