DIY manometer, carb sync and vacuum leak
We picked up an 1100 Custom for my wife about 3 weeks ago. Sputtering, backfiring, popping, surging at cruising speed, etc.
We put fresh gas in, 5 oz Sea Foam and ran it to reserve. We repeated a 2nd time and it was still having issues. On our 3rd tank, we put about 4.5 oz of Berryman's B12. End result was still sputtering, popping, etc.
Before pulling the carbs out, I wanted to take it one step at a time. First on the list: sync carbs. I made my own manometer (pic attached), went to hook up the line to the front vacuum port and lo and behold, it was exposed (no cap). The previous owner put a Kuryakyn Pro-R Hypercharger on the bike and apparently they didn't connect the vacuum hose to the unit.
Long story short, carbs got sync'd, port got plugged, and the bike is running better than ever!
2009 Roadliner Midnight