I have a 1989 Harley Soft-tail custom 1340. When out on the road running, it coughs back through the carburetor and pops through the exhaust. I don't know if it's a shorted wire somewhere, a valve or the jets in the carb wrong. It has a Keihen Carb. On it and Samson street sweeper pipes on it.
Thanks.

Have you changed pipes? If so re-jetting is called for