GL1000 Fuel System questions

[Workinman]

So my Gl1000 seems to be starving for fuel. You can see very little fuel in the clear filter I’m running. And only then when it’s running. I took the fuel line off coming from the petcock and got just a trickle of flow for a while, then it stopped all together. Upon looking into the tank through the sender hole, I noticed that the pickups are actually below the petcock. This leads me to believe that the fuel pump actually SUCKS the fuel out of the tank. Is this a correct assumption? My fuel pump is new, (1600 miles) and it’s a genuine Honda unit. I would HOPE that it’s not bad already, but that’s the only conclusion I can come to. The screens in the tank are clean, the tubes appear to be open, petcock is new, both filters I’m running are clean, and I just can’t seem to get enough fuel to fill the filter. It can almost fill it when idling, but as soon as I increase the rpm it empties it out. Have you guys run into this before?
Your thoughts, please.
Thanks,
Chris

[Old Fogey]

Why do you think it needs to be full, at any time? Are you saying that the bike is not running well? Does it feel like it's starving when you are out on it? If so, first try opening the fuel cap as the vent in that may be blocked.

[WingAdmin]

You're correct. If the tank is above a certain level, it will gravity feed (but not much). Below that, you're not going to get anything without the pump running, so yes, at that point the pump is sucking fuel up from the lower portion of the tank.

You can check your fuel pump against the benchmark specs:

GL1000 Fuel Pump Specs

That said, under normal operation, the fuel filter is not "full" of fuel.

[Workinman]

Hey guys. I guess I should have been more detailed in my post, but I try not to ramble on too much. Yes, I was riding last week, and about 30 miles out the bike started acting like it was starving for fuel. After a few miles of this, it died completely. After sitting for 15 minutes or so, it started back up and I was able to ride it home, although it was a REAL chore! I could only open the throttle to about 1/8 open and then very gently. I could ride for a couple of miles and then would have to pull over. If I let the bike idle for a few minutes, the fuel filter would slowly fill and I could ride a little more. I should also point out that I’m running a stock fuel filter and an additional small clear filter in the line before the stock filter. The reason for this is because while doing the restoration I was not able to get everything out of the tank. I did my own cleaning with electrolysis, and then had the tank cleaned by a radiator shop, but it still wasn’t to my satisfaction so I’m running two filters for the time being. Anyway, finally got the bike home and pulled the fuel lines. I replaced the small fuel filter, which is normally pretty much full of fuel with the exception of one small air bubble, I blew out the stock filter, as it was pretty clean, I ran some wire up into the fuel lines inside the tank, and I blew air into those lines to make sure they were clear. After reassembling everything, fired the bike up and it seemed to run okay. However, the small filter, which is normally pretty much full of fuel, was maybe half full now. Since then, I have taken the bike out for two 50-60 mile rides and it purrs like a kitten. No problems whatsoever. My small filter is still only about 1/3 or so full, and I honestly don’t know how it’s running so damn good with such a small amount of fuel flowing through there, but it is. Normally that filter is so full it’s actually hard to tell if it’s full or empty. Now you can actually see the fuel running through it. I did order another new Honda fuel pump, and it’s sitting on the shelf in case I need it, but as long as it’s running good I think I’ll leave it alone. I don’t know what I did to fix the problem, whether it was replacing the small filter, blowing out the large filter, or cleaning out the lines, but one of those things made the difference so I’ll take it.

[Old Fogey]

My best guess is that your small filter was filling right up because there was a restriction in the lines after it. So blowing out the lines and main filter you ended that restriction. Fuel lines can and do collapse inside. You maybe should change them out. I would also be checking the small micro filters under the float valves. If you system has been that bad, I'll bet they are well choked too.
I can help you with fuel lines and a great filter that comes apart for cleaning, never need to buy another one. https://www.wingovations.com/braidedfuellines

[Workinman]

Fuel lines and filters are pretty much brand new. Carbs are spotless. They were rebuilt by Pistol Pete’s son and then again by myself. I have a new set of braided lines, clamps, and a Honda filter ready to go on. I’ve got roughly 1700 miles on the bike now and I’m hoping that all the crud in the tank will be out soon so that I can install them. I may have even gotten the lines and stuff (that I have set aside) from you, but I honestly don’t remember. I’m guessing, at this point, that either the lines inside the tank were clogged or the small filter was clogged. I couldn’t find the specs in my Honda service manual to check the output of the fuel pump, but now that I have them I’ll be checking that also. Thanks for your help. If I ever figure out what caused my problem, I’ll update this. In the meantime, it seems to be cured, so I’m gonna ride her!