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Vapor lock?

Old Jan 22, 2009 | 04:49 PM
  #1  
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Default Vapor lock?

Bike was running alitte funny after riding for a short time would seem to run out of gas (had plenty of gas) so i would pull over turn to reserve and try again.

But it would do the same thing well i said in an earlier post that my tank would build up air pressure in tank and i would have to unscrew gas cap to let the air out.

So i thought maybe the build up of air was keeping bike from getting gas....


Anyway took rubber seals of my gas caps and tightened them down and noticed that air pressure never got built up in tank and my bike never acted up again for the rest of the day...

anyone think i might of fixed it or have heard of this before....
 

Last edited by bL33d; Jan 22, 2009 at 05:05 PM.
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Old Jan 22, 2009 | 05:08 PM
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Vapor lock is usually associated with carburation not with tank pressure build up...
 
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Old Jan 22, 2009 | 05:16 PM
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Hmm not sure then i am abit stumped which aint hard to do though lol.

Ran great after i took those rubber seals out hopefully it wasent just a fluke.

I had allready changed the ignition as it was corroded pretty good. And got new plugs and wires and bought a new battery. So i guess next time i ride if it does it again i'll get a new solenoid.
 
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Old Jan 22, 2009 | 08:32 PM
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How many miles you got on your ride?? Sure is a clean 91 model.
 
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Old Jan 22, 2009 | 08:36 PM
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24k

thanks
 
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Old Jan 22, 2009 | 08:36 PM
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Originally Posted by bL33d
Bike was running alitte funny after riding for a short time would seem to run out of gas (had plenty of gas) so i would pull over turn to reserve and try again.

But it would do the same thing well i said in an earlier post that my tank would build up air pressure in tank and i would have to unscrew gas cap to let the air out.

So i thought maybe the build up of air was keeping bike from getting gas....



Anyway took rubber seals of my gas caps and tightened them down and noticed that air pressure never got built up in tank and my bike never acted up again for the rest of the day...

anyone think i might of fixed it or have heard of this before....
You've got the right idea, but backwards. The needle in the carb that controls fuel level in the bowl is only capable of holding so much pressure. When that is exceeded, like when your tank built up pressure it floods the carb and runs really rich. Most noticable at idle, due to higher rpms will burn up the overflow of fuel.
Ron
 
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Old Jan 22, 2009 | 08:41 PM
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Ah awesome i hope that fixes it then. Any reason to worry that gas caps are not air tight on tank? aslong as gas dont pour out should be ok?
 
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Old Jan 22, 2009 | 08:47 PM
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I had an 86 FXR that did the same thing. I would loosen the gas cap and it would run fine. I replaced the gas cap and never had any more problems.
 
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Old Jan 22, 2009 | 08:54 PM
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Originally Posted by bL33d
Ah awesome i hope that fixes it then. Any reason to worry that gas caps are not air tight on tank? aslong as gas dont pour out should be ok?
Nope. As long as the gas stays in and keep the water out of that area, you're good to go. There are vented ( both directions) caps or you could improvize with a 1/32" hole drilled in the right place with your present cap.
Ron
 
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