I have removed the vacuum petcock, installed new fuel line (not fuel injected hose) and a quick disconnect from the tank and before the fuel filter.
Bike has been run 3-4 times and each time it dies from no fuel. The tank has been full and 1-2 gallons.
Have disconnected fuel line from fuel filter (quick diconnect connected) and fuel flowed through.
Replaced fuel filter again as there was sediment.
Fuel line was disconnected after the shut off valve also and fuel flowed through.
The fuel starvation issue is noticable at the fuel filter as it can be empty to barely any fuel in it. The bike has sat overnight and the fuel filter is filled with gas. I'm using a Duralast FF3407 part.
Could this issue be caused by the removal of the vacuum petcock? Bike did sit previously for ~ 1.5 years, but ran fine. Have also used the Duralast FF previously.
Picture is attached of current setup w/o vacuum petcock.
(https://uploads.tapatalk-cdn.com/20170331/bea1f43d4404b095d15cc5a43af5ffcc.jpg)
It has to be a vent issue.
Remove the little rubber piece under the fuel cap. It's only used for the vapor canister, and will eliminate vent hose pinching. If it still has an issue it would be internal in the cap.
Thanks. I will check that also.
Quote from: greenohawk69 on March 31, 2017, 09:37:57 AM
Thanks. I will check that also.
If that doesn't work...you mentioned sediment in the filter. If the tank indeed had a build up of loose sediment, it's remotely possible that the fuel outlet from the tank is blocked and is impeding the flow...I want to emphasize the word remotely.
I thought that might be an issue too and ran a hose through the tank yesterday and drained it. Flow out appeared to be ok. Flow appeared ok with gas when I drained and filted into gas cans. Will also filter gas from can to tank. And a new a filter was installed. :)
Hate it when my flow is interrupted.
My Triumph had a similar issue but it was just due to a loose fuel pump relay.
Carby Monsters really don't require all that much flow.
I'm betting that rubber piece under the cap is distorted and blocking the vent hole in the cap, the vent hose under the tank is pinched, or the steel tube inside the tank is blocked.
Removing the rubber piece solves all three issues.
It appears I solved this issue. I flipped the FF 180* so the gas flows via gravity and not upwards like the stock location.(https://uploads.tapatalk-cdn.com/20170402/a0fc42e97530e1dc2a6cccec14d0fef1.jpg)(https://uploads.tapatalk-cdn.com/20170402/c98244be6d9444769beef28c295f46c1.jpg)
My fuel filter is in the stock location and it seems to work fine.
Something is going on. ???
Have you run the gas tank low and experienced any issues? Has the fuel range on the tank the same with and without the vacuum petcock?
Would I be able to snake the in/out vents underneath the tank for blockage (e.g. using stiff wire)?
Quote from: greenohawk69 on April 04, 2017, 01:51:43 PM
Have you run the gas tank low and experienced any issues? Has the fuel range on the tank the same with and without the vacuum petcock?
I've gone 150 miles on a tank with no issues. The most I'd gone before was 160ish.
Quote from: greenohawk69 on April 04, 2017, 01:53:40 PM
Would I be able to snake the in/out vents underneath the tank for blockage (e.g. using stiff wire)?
Try it from the top. Did you remove that rubber piece from under the cap? That is the vent line. If the rubber piece is gone the vent tube amounts to squat. The one on the side that you can't really see unless you remove the cap is the drain.
Yes, the rubber piece under the cap was removed.
I think I used the wrong term. The overflow tubes/vents underneath the tank - with the rubber hose attached.
I understood what you meant. My point is that if the rubber piece has been removed, and you're still not flowing fuel, either the cap is defective, or you have a flow restriction. Snaking the tubes in the tank won't help.
Try running the bike with the cap open.
Is there a way to fix the cap? Askig as I did remove it and paint it after taking most of the bike apart.
Quote from: greenohawk69 on April 04, 2017, 03:37:49 PM
Is there a way to fix the cap? Askig as I did remove it and paint it after taking most of the bike apart.
On the underside of the cap, where the rubber piece meets it, there is a hole. It's possible you got some paint in there, or the rubber flapper things have just stuck. I wouldn't try to disassemble it. There's about 11ty billion little pieces that can go flying. I have experience with that part. I'd try spraying a little silicone spray, or maybe wd-40 and blowing some compressed air in that hole, and the one that is visible on the part that's inside the tank when the cap's closed. Maybe you can get it freed up.
Ok, thanks.
+1. This is a good thing to do periodically to stop crud building up. Its good to have a compressor in the shed. You can check to see if air is flowing freely from the end of the breather and overflow hoses.
It seemed to be ok when I originally removed it and ran over flowing water through it twice. Not sure if the painter ran compressed air through when they finished. I did put gas in it, then drained it and ran water through it again. Gas drained fine as did water. I've replaced the fuel filter twice (saw some sediment I did not like) and have a third one ready.
Quote from: koko64 on April 04, 2017, 04:59:16 PM
+1. This is a good thing to do periodically to stop crud building up. Its good to have a compressor in the shed. You can check to see if air is flowing freely from the end of the breather and overflow hoses.
I think he might have a stuck rubber flapper valves in the cap T.
Either that, or he has a restriction in the tank outlet from the sediment he keeps mentioning.
Thanks. I will see how I clean these areas.
Any suggestions on how to clean these areas - I don't have an air compressor in my garage.
Gotcha DP. Open cap running will tell.
You need compressed air really.
If a simple vent issue isnt found then you need to test some other stuff.
Be interesting to see if fuel flows well to the carbs when bypassing the pump. You need a full tank to test that. Pump failure is not common but E fuels may attack the pumps membranes.
Good to check the manifold to pump vacuum hose first. If its ruptured then the pump won't pulse (known to happen).
Maybe the little carb mesh filter in the T piece is gummed up (possible) or the carbs have gummed up float needles (unlikely).
Quote from: greenohawk69 on April 04, 2017, 05:22:14 PM
Thanks. I will see how I clean these areas.
Any suggestions on how to clean these areas - I don't have an air compressor in my garage.
Spray them down with some wd-40, let them sit, and head down to a local auto, moto, or bicycle shop and ask them if they can blow some compressed air though the holes, in each direction. 30-40 psi should do it.
Running with the cap open will tell a lot. You should really do this first.
If the problem is gone, the issue is in the cap. If not, you have a problem in the other direction...the feed side.
You can chase maybes, or you can chart a course and eliminate items one by one.
Thank you.
Let us know how you go.
Drained the tank 2x and blew compressed air through it 2x. When the tank is off the bike, the gas flows easily through the fuel filter when I open the shut-off.
When I put the tank back on and the fuel line is connected to the line flowing to the fuel pump, the gas does not flow through the fuel filter. Nothing changes with the fuel cap open or closed.
Sent from my SM-G860P using Tapatalk
You'll need to give the fuel a place to go to see if it flows, if that makes sense.
With the pump in the system the diaphragm stops the flow until it draws it from the tank. Can you disconnect the line after the petcock?
Koko above mentioned bypassing the pump directly to the carb to see if the gas flows.
Sent from my SM-G860P using Tapatalk
Quote from: ducpainter on April 10, 2017, 03:16:33 AM
You'll need to give the fuel a place to go to see if it flows, if that makes sense.
With the pump in the system the diaphragm stops the flow until it draws it from the tank. Can you disconnect the line after the petcock?
I removed the vacuum petcock.
Gas flows from tank through quick disconnect - fuel filter - shut-off valve without any problems.
Gas doesn't flow when the shut-off valve is connected to the fuel line - fuel pump.
Vacuum line from fuel pump to manifold appeared to be ok after inspection. What is the diameter of this line? Probably just replace it as it is old.
I know you removed the vacuum petcock...I was referring to the manual petcock/shutoff.
That's normal. Fuel won't flow with the engine off if you have a fuel pump between the tank and the carbs. It also won't flow if the float bowls are full. There's no place for it to go. Even with the engine running you wouldn't be able to observe flow because the fuel requirement is so low. You could disconnect the fuel line at the carbs and crank the engine. Fuel should spurt from the line with the vacuum pulses from the engine. It won't do this until the lines/pump/filter are full.
The vacuum line is probably 5mm. 3/16" is the closest inch size.
ETA...If you crank the motor with a dry fuel filter you should see fuel start to fill the filter.
Tried to crank with fuel line unattached at the carb. No dice
Re-connected fuel line and still not cranking over. Seems like it wants to.
Ran fuel line through the fuel pump and also directly to the carb (poured a small amount in the carb to assist starting).
Got the bike to start both ways, but not for more than 10-15 seconds at best and just quits like it is not getting fuel.
Fuel lines, vacuum lines and tank vent lines are all new, as is the vacuum cap for closed off spigot for the removed vacuum petcock.
I've used compressed air on the tank and all vents and have changed out the fuel filter six times.
My guess is I may have a carb issue (e.g. blockage) somewhere.
There is a filter many people seem to not know about before the carbs. It is located where the line from the pump enters the carbs (assuming it is still there)..
Does fuel come out of the fuel line when disconnected from the pump and the manual tap is turned on? Yes or no? Does fuel come out of the fuel line if disconnected from the carbs, and the starter is cranked? Yes or no?
Howie - I did find the carb fuel filter and it was pretty much clean.
Dp - Yes. Yes.
Got it to run a bit, but was popping through the carb (mainly left side/vertical cylinder) and also popping via the exhaust (right side).
Also had some smoke coming out of the exhaust.
Clean the carbs.
Carbs were gunked up. Gel around the jets/openings. Soaked and cleaned up.
Ran it this AM and it appears to me (not a tuner by any means) that I'm running rich.
Appears to be a 175 jet and not sure about the slow jet.
Needle jet is on 5th clip and had 1 washer underneath the jet, in addition to the thicker plastic washer.
Bike starts up and idles ok. Got on tje freeway and it pulled fine with no drop off. I do get quite a bit of decel popping.
What suggestions do you have?(https://uploads.tapatalk-cdn.com/20170527/c3ca4ed860024778d77a6f29fe47977c.jpg)(https://uploads.tapatalk-cdn.com/20170527/6546f1cbde1bb7d5fdb314f3286e7929.jpg)(https://uploads.tapatalk-cdn.com/20170527/6f007372a6f52937264d7501720b9225.jpg)
Engine mods?
Full system/cans/stock exhaust?
Pods/open airbox/ stock lid?
400/600/750/900?
No engine mods that I know of.
97 M900.
Stock with CF exhaust (Sil Motor).
Open airbox with K&N.(https://uploads.tapatalk-cdn.com/20170527/161064d2889b7f35244d78036a38bf0a.jpg)(https://uploads.tapatalk-cdn.com/20170527/11824516dce7be5c2c492469e3f6c24a.jpg)
If they are Dynojet main jets then that equals roughly 165 in Mikuni jets. If there is no mark identifying them as Dynojet jets and they have the little Mikuni symbol then they are way too large by about 4 sizes at least. Maybe they are Mikuni copies.
I run Mikuni 165 mains (175DJ) with an open airbox, but your local guys will have jetting specs for your fuel.
You should check the needles for markings to see what you have. Pics will help local guys identify the needles and what clip position is best for your intake mods.
I would give the carb an overhaul with new Factory Pro needle jets (emulsion tubes) if they are stockers with more than 10,000 miles on them. It's ok to pay a pro to overhaul carbs if you are not confident doing it.
Nice looking bike.
Hi greenohawk69, where did you get that neat-o fuel filter with the clear housing? I need to replace mine and want THAT one :)
From Autozone, FF3407DL, and has been hanging up on the wall by the other fuel filters, ~ $3-4.
Quote from: greenohawk69 on June 22, 2017, 10:37:39 AM
From Autozone, FF3407DL, and has been hanging up on the wall by the other fuel filters, ~ $3-4.
Thank you! picking one up today after work [thumbsup]
I think i've got a plugged or pinched vent hose problem [roll] Riding for 30+ miles causes fuel starvation and it's remedied by opening the fuel cap...i get a loud WHOOOOSH, close the cap and i'm good to go for another 30/40 miles ;D
I have no canister or the hosing for it, so i'm going to take y'alls advice and remove the black rubber piece inside the cap. Is it the one sitting there next to the fill hole? Looks like i can pull it out with needle-nose pliers...
Also, it's time to replace ALL of my fuel lines and the overflow line. Can you guys recommend which brand/type of hose I should go buy? My fuel lines touch the heads, too so it's gotta be high-temp stuff.....and it's obviously exposed to the elements.
(bike is a 900 but started life as a 750 so it's got the 750 tank/lines setup)
thanks a million in advance.
Didn't we already cover that? :P
That's the one. Some have a dab of glue holding them in. Usually you can just use your fingers.
Quote from: ducpainter on June 23, 2017, 10:27:46 AM
Didn't we already cover that? :P
That's the one. Some have a dab of glue holding them in. Usually you can just use your fingers.
Ahh yes, got it. Sorry for the brain-fart it's been a rough day at work. Thanks for the help as always.
Quote from: ducpainter on June 23, 2017, 10:27:46 AM
That's the one. Some have a dab of glue holding them in. Usually you can just use your fingers.
Removing that rubber plug-thing seems to have done the trick. Neither fuel starvation nor air-whooosh has occurred since removal. I even blew some air through the vent tube to make sure...clean and clear.
For the sake of preventative main't, I purchased a new fuel filter, 4mm vacuum hose, 5/16 & 1/4 fuel hose for the entire system + clamps. Will be installing this week.
Thanks for the help guys and sorry to pile on your thread, greenohawk69 :)