Bike runs fine, then doesn't

[thiber]

Hello guys. I just bought an 86 virago and she'll start right up and ride smooth for a short amount of time (5 min or so?) and then start to lose power and wants to die. Any ideas what it could be? Not getting enough gas/too much gas? Sticking float valve?

Ive replaced oil and filter, spark plugs, new gas, and sea foamed.

[Wrider]

Does it run better with the choke on when it's trying to die? I'm betting it's running rich, so the choke will kill it even faster.

[Johnj]

Check the fuel tank vent.

[thiber]

Does it run better with the choke on when it's trying to die? I'm betting it's running rich, so the choke will kill it even faster.

Havent tried that!

Check the fuel tank vent.

Would that be my air box going from the tank into the carb? If so I just replaced that and should be fine. There may be gas flowing into their when its dying which could cause the problem. Hence the loss of power.

[BRUMBEAR]

If there is gas in there Float is stuck or rather pin is stuck down on the carb.

this is probably your problem it is attached to the float and turns on and off fuel flow.
The vent John is talking about is in every cap or tank itself and stops vapor lock from occuring. So open your cap and see if it stays running if there is no excess fuel flowing.

[GS_in_CO]

The vent John is talking about is in every cap or tank itself and stops vapor lock from occuring. So open your cap and see if it stays running if there is no excess fuel flowing.

You're thinking of something else.

The vent allows air into the tank to replace fuel as the fuel is used. If the vent is blocked then fuel can't get out of the tank as freely as it should. (Picture how you can hold fluid in a drinking straw by putting your finger over the end before you lift it out of the cup or glass.)

[thiber]

If there is gas in there Float is stuck or rather pin is stuck down on the carb.

this is probably your problem it is attached to the float and turns on and off fuel flow.
The vent John is talking about is in every cap or tank itself and stops vapor lock from occuring. So open your cap and see if it stays running if there is no excess fuel flowing.

I will try opening the cap and seeing if that works! If my float is indeed stuck should I try tapping on the carbs? Ive read that worked sometimes.

The vent John is talking about is in every cap or tank itself and stops vapor lock from occuring. So open your cap and see if it stays running if there is no excess fuel flowing.

You're thinking of something else.

The vent allows air into the tank to replace fuel as the fuel is used. If the vent is blocked then fuel can't get out of the tank as freely as it should. (Picture how you can hold fluid in a drinking straw by putting your finger over the end before you lift it out of the cup or glass.)

Any idea where this vent would be on a virago?

[GS_in_CO]

Any idea where this vent would be on a virago?

Start looking for it on the cap.
But the easy test is to loosen the cap and see if the bike runs differently. In some cases you can hear air rushing into the tank as the cap is loosened but not necessarily.

[thiber]

Ran it with cap off, no change in riding. Still sounding crappy and little power.

[BRUMBEAR]

Carb is the problem,
GS, not thinking the wrong thing just typing it I should have typed air lock not vapor thanks but the end effect is no air in equals no fuel out and it's moot now If there is fuel in the airbox and the bike runs poorly you need to pull the carb or carbs and clean the varnish off the jets and seats andclean thefloats and "bullet" valve.
Note: check your tank for rust it may indeed be a problem and will give you fits if not corrected.