81 650 maxim keeps dying

So I was riding merrily along yesterday on my 81 650 maxim when it started hesitating and as soon as I drifted to the side of the road and let off the gas it would die. When the choke was open and the petcock was turned to PRI it seemed to run, albeit at high rpms, enough for me to get home. I just cleaned the carbs about 250 miles ago and the bike only has 2200 miles on it. I am a bit confused. The fuel line has a filter on it and I had not had any problems since I cleaned the carbs. It sure seems like a fuel problem though. Ideas?

 

I’m sure you check this but 2 weekends ago I was riding and had nearly the same thing happen to me. I ahh how should I put this…. Ran out of gas… well not all the way but low enough that in the ON pos gas wasn’t flowing but it would in the PRI pos. Wait I have an excuse. See I had been rebuilding my bike and had used the half gallon of gas from my lawn mower can. Got the bike running drove around the “hood” for awhile then she starts to cut out. So back in the garage I pull the tank there seems to be gas, it flows on Pri but when I hook up a vacuum pump the the vac line on the tank NO gas. I’m thinking bad petcock valve. So since it was so nice out I figure I’ll drive on Pri for today and order a petcock valve. While I’m out I stop for gas, I reach down flip the valve to ON because the bike is off and sometimes the head pressure from the gas in the tank over runs the float valves in Pri and I don’t want to flood the bike at the gas station. I start the bike and drive. 15 min into the ride I relized that I never flipped the valve back to Pri. and here I am running fine. So I guess what I’m trying to say long winded is look for the easy first and ahhh don’t run out of gas.

 

Have a close look at the vacuum line from the intake manifold to the petcock. A split hose or lost connection would simultaneously close the vacuum valve at the petcock, stopping the fuel flow, until you select Prime ... and, introduce more air, causing the higher rpm's, when the engine is re-started.

 

It seems like there is gas in there, but I'll fill her up just the same and see what happens. I have proven myself retarded several times, hopefully this will be another one and nothing needs fixing. Thanks.

 

I've done the same, My previous bike (81 xs400) got 250 kms to atank of gas, so when my 650 died after 150 kms I panicked, and same thing drove it on prime, filled it up at the has station, and no problems!