Author Topic: Out of gas (not really)  (Read 529 times)

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Offline TNConnieRider

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Out of gas (not really)
« on: April 26, 2018, 04:54:15 pm »
My son and I traded bikes one day and in the rear view mirror, I see him on my 95 Concours pulling to side of road. He says that is just died as if out of gas. The gauge shows 1/4 tank and no where near needing reserve but hey, those have been wrong before. Flopped to reserve, a little choke and nothing. Popped the lid on tank, saw fuel then it started right up. No more issues. Last week, same thing again. Seems to be intermittent and only when tank is at lower level but not every time. Seems to have a vacuum that is relieved when I open the lid allowing fuel to flow again.
The pet c*** was replaced by previous owner and looks like Murphs manual pet c*** conversion. Also has overflow tubes on carbs and lots of other goodies (PO was COG member).

Any thought what can be causing this?
Honda MiniTrail 50, Yamaha GT 80, Suzuki TC 100, Yamaha DT 125, Kawasaki KZ 400 Ltd   Kawasaki KX 125, Suzuki RM250, Kawasaki ZX600,Kawasaki Concours C10 (#1) Suzuki Boulevard C50,Kawasaki Concours C10 (#2)

Offline Rob

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Re: Out of gas (not really)
« Reply #1 on: April 26, 2018, 05:52:06 pm »
Vent in the gas cap.

Offline Hardhead

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Re: Out of gas (not really)
« Reply #2 on: April 28, 2018, 10:53:41 am »
My son and I traded bikes one day and in the rear view mirror, I see him on my 95 Concours pulling to side of road. He says that is just died as if out of gas. The gauge shows 1/4 tank and no where near needing reserve but hey, those have been wrong before. Flopped to reserve, a little choke and nothing. Popped the lid on tank, saw fuel then it started right up. No more issues. Last week, same thing again. Seems to be intermittent and only when tank is at lower level but not every time. Seems to have a vacuum that is relieved when I open the lid allowing fuel to flow again.
The pet c*** was replaced by previous owner and looks like Murphs manual pet c*** conversion. Also has overflow tubes on carbs and lots of other goodies (PO was COG member).

Any thought what can be causing this?
You need to disable the tank vent in the gas cap. Try to  do a search on the form. I know many years ago I did a how to on the vents. HTH JD

Offline JPD

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Re: Out of gas (not really)
« Reply #3 on: April 28, 2018, 03:25:36 pm »
You need to clean or repair the vent in the tank. It has 2 functions, 1 vent air in while riding,2vent air out when it expands due to heating.

Offline Stasch

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Re: Out of gas (not really)
« Reply #4 on: May 26, 2018, 04:20:40 am »
or non OEM fuel line routing issue trying to bend 90 degrees which when kinks shut when hot?  Inline filter?

Edited 5/26/2018 to Add:

I wrote the above on a tablet with virtual keyboard - a bit wonky.  This will round it out a bit more.

If you are using non OEM fuel line such as clear / tinted Tygon or similar, they can kink shut due to heat making them so flexible they collapse at the bend when conditions are right.  This can occur if the bends are too much, say 90 degrees to route down to the carb fuel inlet from the petcock. 

This situation can be a tough one to isolate, since by the time you get the tank off back home in the garage, the line appears normal.

Pulled my hair out when I went through this in around 2004 with my C10.
« Last Edit: May 26, 2018, 09:17:27 pm by Stasch »
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He IS a racer, hence the forward lean!!  by: Mettler1

Offline Cap'n Bob

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Re: Out of gas (not really)
« Reply #5 on: May 26, 2018, 06:42:10 pm »
Clogged vent, kinked fuel line between petcock and carbs, or possible a clogged filter. Even though the petcock is newer doesn't necessarily mean that gunk didn't clog up the screen. And of course possibly a clogged external filter to go with the kinked hose if you have an external fuel filter. These would be my guess if it is indeed starving for fuel.







Note: wow auto spell added by auto censor. Got to love it. Hope I fixed it.    :))
« Last Edit: May 26, 2018, 07:26:11 pm by Cap'n Bob »

Offline cra-z1000

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Re: Out of gas (not really)
« Reply #6 on: May 26, 2018, 11:01:48 pm »
or non OEM fuel line routing issue trying to bend 90 degrees which when kinks shut when hot?  Inline filter?

Edited 5/26/2018 to Add:

I wrote the above on a tablet with virtual keyboard - a bit wonky.  This will round it out a bit more.

If you are using non OEM fuel line such as clear / tinted Tygon or similar, they can kink shut due to heat making them so flexible they collapse at the bend when conditions are right.  This can occur if the bends are too much, say 90 degrees to route down to the carb fuel inlet from the petcock. 

This situation can be a tough one to isolate, since by the time you get the tank off back home in the garage, the line appears normal.

Pulled my hair out when I went through this in around 2004 with my C10.

This was one of the first issues I had with my c10 , tygon fuel line was way too flimsy , kinked just enough that if the tank was half full , there seemed to not be enough flow. 
1987 C 10
80 Kawasaki KZ 1000 MK 2
74 Honda 750 four ss
73 Suzuki 550 triple
72 Honda 550 four