Kind of at a loss here...hopefully one of you has some insight into what's wrong. I was riding yesterday, bike running great, down the interstate doing about 65-70mph. Fuel gauge reading just off the "F" and which would be correct as I have only gone about 65 miles since fill up. Out of nowhere, she starts stumbling a little, like the beginning stages of running out of gas, or when the battery cables are not tight. But it is intermittent, as she bogs a little, then picks up and runs right a few seconds, then it happens again. This progresses in the span of about a minute into full blown "bike died" as I am pulling onto the shoulder. I open the fuel tank, and the tank is indeed almost full. I try to restart and she turns over fine, but no start. Switch it to reserve, same result. Put it back to the "on" position, try cranking and it does eventually start. Revs fine, no lag, nothing wrong.
Put her in gear and start to pull off, and under load, she bucks like she is misfiring and has all the power of a 50cc moped. I go through the gears to get to the next exit so I can get off the interstate and, under WOT, achieve only 58mph max. She is firing on both cylinders as I can hear both pipes barking like they do when I am running it hard. In fact, just short of WOT is the only way to keep any momentum. However, when I get off the interstate, she runs fine. Does not die, revs just fine to 5 or 6K rpms, which is where I quit revving, so presume it would have gone higher had i twisted the throttle that far.
Plugs look fine, and were replaced about 6 months ago. I originally thought maybe it was the R/R crapping out as I have read about some of the stuff happening to others on the forum, so perhaps it was the spark plugs were not getting enough voltage to fire correctly causing a constant misfire. However, with it revving fine under no load and idling normally, it did not really stack up. Ditto for trash in the carbs, which should have nothing wrong at all since the tank and fuel lines were flushed out, and the carbs have been cleaned. Headlight works, all the are gauge lights are bright...nothing out of the ordinary with the electrics I can find, and I have a Yuasa AGM that is about a year old. Gas was from a 5 gallon container I had previously filled up with and ridden out with no problems within the previous week.
Can somebody offer some insight? My Vulcan has turned me into a "Do-it-yourself-er" and I have moderate troubleshooting skills, but I confess some of the maladies confound me.