I found a quick way to do it as long as you don't mind damaging the stock baffle. Use a slide hammer. Find a large nut that fits the end of the threaded rod on the slide hammer and zap (weld) the nut on the end of the baffle. I just held the spark arrestor in a vise and worked the baffle out using the slide hammer in a few seconds. Could use some spray lubricant first to try and free things up before pulling it. If you don't have these tools, take it to a garage - they should have a slide hammer, etc. Literally, the whole operation took 5-10min.