[miroku800]

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every time I take the bike out for about 50 miles I find the fuel filter is empty but there appears to be enough fuel coming through to keep the bike running, so could some of you take note of how full your fuel filter is before a run and check it after a 'reasonable' distance and see if it is full, empty or what and post the results.
I am trying to find out if I have an air leak in the fuel line and its sucking air instead of fuel

Many thanks for any info

Regards Rob

 

[agnogel]

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hi rob i have never seen a fuel filter full on any machine you dont say if your haveing probs with the bike or is this just some thing you noticed

 

[exavid]

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About the only way you can purge the air from the fuel filter is to get the filter vertical instead of horizontal. The easiest way to do that is to disconnect the carb end and hold the filter vertical then turn on the fuel petcock. The air should migrate up into the tank. It really doesn't matter if there's air in the filter, as long as you pump gas out of one end gas will flow into the other. The trapped air really doesn't make much difference.

 

[Wingnumberone]

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I wouldn't worry about the fuel line "sucking air". It's under fuel pressure from the pump.

 

[jackjohn]

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Mine runs with an air bubble in it but is generally about 3/4 full of fuel.

 

[miroku800]

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jackjohn wrote:

Mine runs with an air bubble in it but is generally about 3/4 full of fuel.

Thats what I would expect and if I let the bike stand with the tank full and the petcock on it fills up quite nicely, but by the time its been for a reasonable run it is back to empty.
Which suggests the pump is drawing more fuel than the tank and pipes can supply but I have checked for blockages replaced pipes and have a good flow from tap, so the only thing I could think of was an air leak under suction 'pressure'.

The pump has been replaced with that from my spare engine but that made no difference

The tank cap has been cleaned and checked and have tried running with it loose with no result.
I have got one of Randakks petcock kits but will have to wait for the tank to be almost empty till I can fit it as I have to drill the rivets out and rethread it

The bike starts and runs reasonably well but I suspect it is struggling when the speeds get higher, as what the pump is drawing is going straight to the carbs with no 'spare' fuel.

All ideas much appreciated, is there anyone else taken any notice of how full their filter stays

 

[sle104]

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Ive had 2 1100 an 82 and now a 83 both were the same as yours. I have never had a problem.

 

[goldwingnut]

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If your filter is horizontal and fills ip all the way I would think the filter itself has a leak.

 

[miroku800]

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wrote:

If your filter is horizontal and fills ip all the way I would think the filter itself has a leak.

Unfortunately this is the second filter and there is no sign of weeping (it only fills right up if its left with the petcock on, and a full tank for a lengthy time)

 

[miroku800]

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sle104 wrote:

Ive had 2 1100 an 82 and now a 83 both were the same as yours. I have never had a problem.

I looks like it may just be some bikes then and I may be worrying unneccessarily

 

[OldNewbie]

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Kinda old school but i always thought that served as an indicator of the filters condition. low level = fuel is getting thru easy. high level = nearly plugged up media...time to replace. True, you always wonder how liquid fuel gets out when air is on top, but it does.

 

[miroku800]

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Its more the fact that it appears to be running 'dry' thats puzzling me!!

 

[chris in va]

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I know, I know...the Gl1100's are a real hotrod and all. But seriously you need to lay off the throttle some, mmkay?:dude:

 

[exavid]

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Once a fuel filter is filled there's only a few ways for it to empty. First of course is if the tank goes empty. Other than that you'd need to have either air introduced through an air leak in the petcock or fuel line attachments or the fuel line itself. The other source would be fuel vapor in the filter if it gets heated quite a bit from an outside source. If you have an air leak between the tank and filter it's possible to suck the filter dry to the point bubbles show up on the fuel pump's intake side which greatly limits the fuel delivery to the carbs. The fact that you say it happens with less than a full tank makes me suspect the petcock or fuel line in the tank. Try leaving the petcock on reserve to see if there's a leak on the normal side of the pickup. The business of drawing air with half a tank also corresponds to the fact that these tanks don't gravity feed well below half a tank. One other test you could try would be to disconnect the fuel line from the carb when the tank is full and see if you can drain the contents of the tank into a bucket via gravity. If there's no air leak most of the tank contents should drain, with an air leak in the tank or line there will be no siphon action so the fuel will quit running around half a tank.

 

[Hobie1]

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Greetings,

Do you have the filter pointed in the right direction for the fuel flow? You also might try hooking up an air compressor line to the fuel line(ahead of the filter), with the pressure dialed way down, and with the fuel cap off and hopefully little fuel in the tank, and just give it a little blast of air. You might have some crud built up in the tank and this might clear it free of the intake. If that is the case, you'll still need to address the issue of crap in the tank.

The fuel pump can only provide fuel flow to the carbs at a rate that is determined by whats available from the feed. If there is restriction the pump will just cavitate.

Good luck in your venture.

Hobie

 

[miroku800]

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Hobie1 wrote:

Greetings,

Do you have the filter pointed in the right direction for the fuel flow? You also might try hooking up an air compressor line to the fuel line(ahead of the filter), with the pressure dialed way down, and with the fuel cap off and hopefully little fuel in the tank, and just give it a little blast of air. You might have some crud built up in the tank and this might clear it free of the intake. If that is the case, you'll still need to address the issue of crap in the tank.

The fuel pump can only provide fuel flow to the carbs at a rate that is determined by whats available from the feed. If there is restriction the pump will just cavitate.

Good luck in your venture.

Hobie

thanks for that, but unfortunately already tried that one (the air) with no problems also had a wire up both pipes in the tank, tank is as clean as the proverbial whistle