Hi guys. My '34 developed a misfire yesterday when I was out for a 20 mile drive. It is noticeable at all speeds, under load and not. I checked all the plugs and none were fouled. It seems to be more noticeable on a cold start and less so when the motor warms up, but never goes away. I notice a bit of smoke from the filler tube which smells like exhaust, so I suspect I may have a sticky valve. I drizzled about 6 ounces of MMO down the carb under fast idle, but still have the misfire. Any advice on what to check next would be appreciated. Here is a link to a 30 second video of the motor running.
https://photos.app.goo.gl/1698PpxL9Xg7jNNX7
Thanks in advance.