I have a low miles sportster that pings after its been running awhile I'm already putting 93 octane in it it has a stock exhaust will putting a free flowing exhaust make this go away

Putting a free flowing exhaust will likely make it worse.

Pinging is usually caused by a lean mixture when you are using the proper octain fuel. Is this one carburated or fuel injected? High flowing exhaust will lean that out further.

What you may want to try, is mix a 1/4 can of BG44K into a full tank of gas, and run that... you can mix another 1/4 can into a 5 gallon gas can for next fillup... and put the rest in your car... with a full tank and let it help that too.

It will do a wonderful job cleaning either the injectors or jets.

It isn't cheap... but the other cheap stuff is essentually worthless.