wont idle after gas fill up

Drummer99 · May 24, 2017

So I have my commando idling like a kitten at 900 RPM running perfectly I go to the gas station to fill er up bike is still idling perfectly as I pull up to pump I shut her off fill up the tank premium blend Esso This bike has been starting on the first kick ! Kick it over doesn't start a couple more kicks it starts but wont idle at all I cant even let the throttle go to get it off the stand . Take it home same problem. Previously all gas had been poured in from a gas can any ideas possibly dirt in the new gas but seems unlikely ? Drummer 99

o0norton0o · May 24, 2017

Eliminate the "after the fillup" from your question and what is the most common answer to the "won't idle" issue?? Clogged idle jet, so clean them out first. Then see where it goes from taking care of the most likely cause...

Mr. Rick · May 24, 2017

It does not seem likely to me that a bad batch of gas wd affect the bike immediately.
But if you're worried about the gas in the tank, just drain it into a can and start over with something from a different station.
I once filled the wife's car at the local indy station and within a block it was kicking and farting. Turned out the delivery truck had filled the regular underground tank with diesel; lots of unhappy customers!

chaztuna · May 24, 2017

You might have gotten a bad tank of gas. Possibly contaminated with water. Water is heavier than gasoline, so will sink down very quickly. Easy to check. Place a cup or similar [preferably clear] under your carbs. With the petcocks shut off pull the drain plugs from the float bowls. Make sure all the drained fuel goes into the cup/container below. Water will sink to the bottom. Another easy trick is to pour the contents onto a concrete surface. The gas will soak into the concrete leaving a wet stain. Any water will bead up and stay on the surface of the concrete.

bill · May 25, 2017

this kinda rules out a fuel problemas the new fuel has NOT reached the float bowls yet. i would be looking at ignition. what ign do you have? if old boyer could be a low battery?

Drummer99 said:
bike is still idling perfectly as I pull up to pump I shut her off

This bike has been starting on the first kick ! Kick it over doesn't start a couple more kicks it starts but wont idle at all I cant even let the throttle go to get it off the stand .

Drummer 99

GavinJuice · May 27, 2017

Open the gas cap again and see if it goes WHOOSH. If it does, it's not venting properly and holding a vacuum in the tank preventing fuel to flow.

worntorn · May 27, 2017

A sticky float on one carb will do this. On my 850 it's the right side carb at the moment. The bike normally idles perfectly but every now and then I pull up to a stoplight and it will either die or idle rough. Every time this occurs there is gas dripping from the carb. It's definitely worse with a full tank, I guess there is that much more pressure on the float needle.
Time for a new float and needle for or better still, a pair of new Premieres.
This could be your problem as well .

Glen

concours · May 28, 2017

Drummer99 said:
So I have my commando idling like a kitten at 900 RPM running perfectly I go to the gas station to fill er up bike is still idling perfectly as I pull up to pump I shut her off fill up the tank premium blend Esso This bike has been starting on the first kick ! Kick it over doesn't start a couple more kicks it starts but wont idle at all I cant even let the throttle go to get it off the stand . Take it home same problem. Previously all gas had been poured in from a gas can any ideas possibly dirt in the new gas but seems unlikely ? Drummer 99

Did it cough at ALL while attempting to start?

Check the intake manifold crossover hasn't popped off.

BillT · May 31, 2017

concours said:
Check the intake manifold crossover hasn't popped off.

This will cause a massive vacuum leak, making the bike not want to run at all below 2000 RPM. One kickback on the restart could pop the transfer pipe off one of the nipples, and one might not notice it right away.

Drummer99 · Jun 1, 2017

thanks for all the feedback I assumed it had to have something to do with filling the tank up I took 2 gallons of gas out and it purrs like a kitten again How does the gas tank breathe could it have been a vapour lock?
Thx Drummer 99

dero · Jun 1, 2017

If you opened the cap to fill the tank , then the problem started , I would think it highly unlikely it is a tank vent problem .

kommando · Jun 1, 2017

There is a labyrinth breather in the cap, the exit is the small hole in the top and the entrance is the small hole on the underside of the cap, easily blocked as it has a tortuous route so it does not leak petrol and only allows air in to replace the used petrol. When blocked it will take a few miles before the petrol stops flowing and you can run again for another few miles by opening the cap and closing it again.