I bought a semi-neglected Valkyrie Standard and made it my project bike.

Can't seem to figure out how to post a picture.
It had 3x3 Two Brothers exhaust pipes coming off the headers and that were cut off just past the rear brackets. It was super loud, too loud.
So I bought stock exhaust off of eBay and now that I've installed them, the left side pipes started to smoke and choke up the bike and now it won't start at all. I didn't smell anything in the smoke (like dead rodent or burning dirt/dust).
Any ideas of the cause??
I had to take the engine guards off and decided to put them back on before I checked how it's running. Grrrrrrrr. I'm hoping there might be an easy fix...