Fuel line issues

Ok, here is what I have. I am the new owner of a 1982 KZ1100 A2 shaft,11000 miles. As far as I can tell completely stock. I put on a set of pods (no I haven't been able to re-jet carbs)). It does seem to run a little lean of course but I can't complain about performace. I would like to know what the results of this lean running could turn into? Also I am running an inline filter, problem is the gas will stop flowing from tank,air in the filter and carbs will starve for fuel. I take the line off the filter and gas will flow even through the filter, I put back together and sometimes fuel still won't flow? The only thing I can think of to try is going to a bigger fuel line. Anybody ever had this happen? Anybody have any suggestions? Thanks in advance for the help.

Running the engine lean for extended periods of time can cause a lot of damage. I would check the diaphragm in the petcock for damage. Also double check that the fuel lines installed are fuel lines and the hoses haven't been replaced with vacuum/windshield washer fluid lines (I've seen people do that quite a few times :huh: )

Some of the inline filters designed for automobiles (with fuel pumps) don't allow sufficient flow in a gravity-fed system.

For gravity-fed motorcycle fuel systems, need to fit a filter designed for such purpose.

Example:




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I have changed the fuel lines myself with new line since I got the bike. The fuel filter I have been using is the same as the one in the pic. Thanks for the info but need more input on this.

LovinMyKZ wrote: ...am running an inline filter, problem is the gas will stop flowing from tank,air in the filter and carbs will starve for fuel. I take the line off the filter and gas will flow even through the filter, I put back together and sometimes fuel still won't flow? The only thing I can think of to try is going to a bigger fuel line....

take the line off the filter and gas will flow even through the filter -- :S uncertain about what is being described? Could this scenario be re-stated differently -- perhaps in a clearer manner?

Am thinking that size of the fuel line is NOT an issue in this instance.

An obstructed fuel cap vent can cause fuel starvation, but usually happens while riding.

As known, when the engine isn't running, a vacuum-operated petcock is supposed to allow fuel flow only when set in the PRI position.

A kinked fuel line may cause fuel starvation.
Line should be fitted with smooth curves.
Length of the fuel line (below level inside the tank) doesn't matter.

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Thanks for the replies Patton, sorry wasn't clearer description.when I said fuel flowed through filter is when I would turn to prime with the line off the carb side of filter. I reconnect line and turn prime on would still hold air in the filter and not let the fuel flow. It does not do this100% of the time but is getting to be a pita . It seems to be worse at a half a tank or less, also I have cleaned the tank and petcock and carbs.

Thanks for clarifying.

Being "worse at a half a tank or less" casts suspicion toward an obstructed vent in the cap of the fuel tank.

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Ok, today drained the tank, removed and cleaned the petcock, put bigger clear tube from filter to tank ( temporary for diagnoses) test ride produced the following info. It seems at in town speeds and at 55 the line gets full of air, not going up and out through petcock. Just before getting back home opened her up in 3rd and 4th and when I pulled in the line was almost full of fuel,lol. As much as I would love to I cant ride WOT all the time. Any other ideas? I also poped the gas cap open and tried that, still did same thing. I have never heard of this problem before.

Continuing symptoms while test riding with the gas cap ajar would eliminate the possibility of a cap venting issue.

If not already done, could also test ride with the petcock in PRI position, to see if it makes any difference in the symptoms.

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Yes I tried that too still getting air. I am wondering" Why am I getting air in the line anyway? It is new line but am thinking maybe replace it anyway to make sure there are no small holes? There are no leaks anywhere or even a wet spot,IDK. Could air be coming back from the carbs somehow? Thanks for continuing to comment Patton I can see from all the different posts you have a LOT of knowledge about these vintage bikes, RIDE ON Brother

I'm probably not understanding something here but isn't it normal to have some air in the filter ? I doubt my fuel filter is ever more than 50% full of fuel.

Air in the line is perfectly normal. The bottom of the line attaches where the float valve is, and that is above the fuel level. So the line is exposed to air at that end. Fuel runs via gravity through the line into the carb bowl, but that is not a liquid-tight, sealed environment, so air flows up the line. Ed