Hey guys, new to the forum.I have just bought a 97 RSTD. I am getting pretty poor gas mileage.Around 28mpg.Have changed plugs,synced carbs,checked air filter and changed fuel filter.Timing looks good.I think the bike vibrates more than it should at highway speeds,of course I don't know how much it should vibrate if any. It has after market exhaust but dont know if it has been re jetted. I get a lot of popping on decelleration. I am now looking at carb rebuild or a possible problem with the coils. The bike has 36000 mi on it. Any help would be great.