Gmc28 Posted February 17 Author Share Posted February 17 Crank case now vented properly. And she’s all buttoned up, TPS set, CO trim good, valves & plugs, good, TB’s themselves were a mess inside (another reason to not use pods), and last thing left is TBS. Alas… key on, fuel pump gives reassuring whirring sound, but then i notice fuel spraying from positive electrical connection point on the pump. Hmm. Repeat action, same result. Thinking its maybe ricochet from elsewhere, but confirmed its from the positive terminal spot. Only sprays while the pump is running, and its cycling off properly after initial prime. Open the fuel cap on top, and the fuel geyser when pump is on goes from an aggressive spray down to a tiny dribble. So that means tank venting seems logically suspect. Tank was painted, so maybe something got messed up with paint, or my tank vent lines i messed up when installing (unlikely, as thats pretty simple, but I’m certainly not immune from doing the occasional stupid/oops). Or it’s just a bad pump, and all will be well when i replace the pump. Pump runs great, so it’s a bummer, but combo of age, ethanol fuel, and having been sitting for a couple years up on the rack in the shop…. Who knows. Thinking I’ll just order the pump, unless anyone has any other wise thoughts. 1 Link to comment Share on other sites More sharing options...
docc Posted February 18 Share Posted February 18 There is this external fuel pump replacement offered by MGCYCLE: Link to comment Share on other sites More sharing options...
Gmc28 Posted February 18 Author Share Posted February 18 Yessir, that’s the one in my basket with MGCycle. But am still thinking about whether there was more to it…. Did it just fail from sitting there and aging, or was it helped along toward destruction because of something else. Still wondering why it sprayed more fuel when i had the tank cap closed then when it was open. Venting issue comes to mind, so I’ll check for that, but even then why would it behave like that? Link to comment Share on other sites More sharing options...
docc Posted February 18 Share Posted February 18 Collapsed/ clogged fuel filter . . . ? Link to comment Share on other sites More sharing options...
Gmc28 Posted February 18 Author Share Posted February 18 7 minutes ago, docc said: Collapsed/ clogged fuel filter . . . ? Certainly comes to mind, and i have a new filter coming as well. I’m just thinking that even though it’s been sitting for a couple years, which is no small thing when considering causes for issues, but it did run reasonably well before it went into the surgery room. So, new paint on the tank i can’t help but be suspect of… tape, overspray, or something like that perhaps. Gotta get back out to shop and check the return line and vents. Just hard to get motivated to get my butt back out there, sitting here by the fire… Link to comment Share on other sites More sharing options...
gstallons Posted February 18 Share Posted February 18 I don't think the filter or anything else in line could be causing a problem . Do install a new filter when you install a new pump. While you are at it replace all high pressure rubber fuel lines in this circuit. When you tighten the hose clamps on these lines , just get them snug and make suer the clamps are indexed so you can retighten them if necessary . Fuel leaking from the pump means the pump is bad . 2 Link to comment Share on other sites More sharing options...
audiomick Posted February 18 Share Posted February 18 51 minutes ago, Gmc28 said: Venting issue comes to mind, so I’ll check for that, but even then why would it behave like that? The pump delivers into a closed loop that goes back into the tank. If you do have a venting issue, it could mean that the closed cap increases pressure in the loop above what the pressure valve is set to. With the cap open, the venting problem is no longer the dominant factor, and the pressure in the loop is that which the valve is set for. Maybe... Link to comment Share on other sites More sharing options...
Gmc28 Posted February 18 Author Share Posted February 18 All makes some sense. For sure am replacing the filter too. And I’ll see if i can force some air through the tank vents. New pump and filter are enroute…. 1 Link to comment Share on other sites More sharing options...
Lucky Phil Posted February 18 Share Posted February 18 2 hours ago, Gmc28 said: All makes some sense. For sure am replacing the filter too. And I’ll see if i can force some air through the tank vents. New pump and filter are enroute…. Too many variables to this equation on a fuel system thats been dry for an extended period of time and is 25 years old to begin with. I would have changed out the filter as a basic precaution to start with. Any leaking issues with the external pump means it gets replaces. It's got plastic end caps crimped to the pump body, is 20 years old and lives in a hostile environment and any leakage in that area can result in a mobile disaster . I look at mine now and the aging of the plastic and think it's about time to just replace the thing anyway. The venting should be checked as others have pointed out but also the regulator. From personal experience used ones that have been left dry for extended periods like a few months or more can jam closed. You initiated the pump and hear it start and then begin to labour and there's a sudden loud "pop" as it comes unstuck. Maybe yours did unstick and the system over pressurised to an extent and caused the pump end cap sealing to fail? Although the pump itself has an internal pressure relief. To may variables on an aged system as I said. Time to just replace some components. Phil 1 Link to comment Share on other sites More sharing options...
audiomick Posted February 18 Share Posted February 18 3 hours ago, audiomick said: The pump delivers into a closed loop that goes back into the tank.... 2 hours ago, Gmc28 said: All makes some sense... Except, on second thoughts it doesn't. The closed loop goes back into the tank, but it draws from the tank as well. So, theoretically, the net pressure difference around the complete loop, including the tank, should be zero. Unless the venting on the tank can draw air in, but not release back out. Seems unlikely, but who knows. As Phil said, there are too many variables. However, changing the pump and filter seems to be a sensible idea, and checking the venting can't hurt. Link to comment Share on other sites More sharing options...
Gmc28 Posted February 18 Author Share Posted February 18 for sure replacing pump and filter. On order. Did a quick check on the two little vent lines today, and they seem fine: 1 to the charcoal canisters, and 1 to the ground(bottom of bike). The one to the ground has the one way check valve in-line, which worked fine…. It will allow air/fuel to exit tank but not draw back in. Now that I’m caused to think about it, am wondering how the tank vents air IN… via the breathers on the gas cap ring area, or just via the charcoal canister pathway? But also has me thinking about how the return fuel line to tank, the one that goes to right/rear side of tank and into that reg there. How does one test that? When I pulled that fuel line off, the line was quite pressurized…. Sprayed a good bit of gas. I expected it to drain some, but not spray it so forcefully. I had not run the pump since yesterday. thoughts? Link to comment Share on other sites More sharing options...
docc Posted February 18 Share Posted February 18 Good you had a look at the venting. That seems to be in order and in original specification (charcoal canisters). I can't imagine tank venting being the issue here, but a stuck regulator? Yes, how would that be tested? Link to comment Share on other sites More sharing options...
docc Posted February 18 Share Posted February 18 Oh! Wait! Non-sparking! 1 Link to comment Share on other sites More sharing options...
audiomick Posted February 18 Share Posted February 18 21 minutes ago, Gmc28 said: When I pulled that fuel line off, the line was quite pressurized…. Sprayed a good bit of gas. I expected it to drain some, but not spray it so forcefully. I had not run the pump since yesterday. thoughts? I was advised by someone who really knows his stuff to pull the plug on the fuel pump so it is de-activated, start the bike, and let it run till it stops. That relieves the pressure in the system, of course, and is the trick to easily getting the snap-on connectors in the fuel lines open to, for instance, remove the tank. Link to comment Share on other sites More sharing options...
docc Posted February 18 Share Posted February 18 2 minutes ago, audiomick said: I was advised by someone who really knows his stuff to pull the plug on the fuel pump so it is de-activated, start the bike, and let it run till it stops. That relieves the pressure in the system, of course, and is the trick to getting the snap-on connectors in the fuel lines open to, for instance, remove the tank. A non-issue with the early V11 Sport with the external tank like @Gmc28's Greenie. Yet, still a valid way to depressurize the fuel system. Link to comment Share on other sites More sharing options...
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