Won't stay running

[Winddancer]

the fuel pump has been completly disconnected and it is out of the loop, per se, so it is not the problem, (the pump itself seems to be fine though.)

I had run the bike to drain down the carbs, and it was stuttering from the lack of fuel, so I know the carbs were low, but I will completly drain them when I get home..

the vent hose, or the actual hose collapsing sounds more like a route to investigate, and I will do that when I get home also..

Thank you all for the suggestions...

i will update the results

[V7Goose]

Based on everything I think I remember from this thread, I do not think you have actually removed the petcock from the tank. If not, then I would bet many $$ that you have crud and water in the tank that is blocking the screen. This sort of thing does not STAY blocked, and blowing air back into the tank doesn't prove a thing - it simply pushes the crud away from the screen for a short while.

 

Remove the petcock and let all gas drain out the hole. Do not pour ANY of it back in without letting it settle for an hour or two to allow the very small water droplets to coalesce into a pool at the bottom. If you do try to re-use the gas, be very careful not to let some of the water and other crud in the bottom pour out.

Goose

[Winddancer]

V7Goose

Yup pulled the petcock (refer to post #19), and checked filter.. clean as a whistle..

getting ready to go out and test the vent hose's and integrity of the lines themselves.

[Mad Dog]

I'm amazed at the amount of help available through this forum. Can't wait to see where this ends up!

 

GL Winddancer

[V7Goose]

V7Goose

Yup pulled the petcock (refer to post #19), and checked filter.. clean as a whistle..

getting ready to go out and test the vent hose's and integrity of the lines themselves.

In post 19 you said you turned the tank upside down and pulled the petcock - you said nothing about draining the fuel. As I said above, this type of problem is typical of water and crud blocking the screen, and that stuff will simply wash off as soon as you slosh the tank.

 

You may have a blocked vent, but unless the tank is filled to the absolute brim, you can ride for a very long way until the vacuum caused by the used gas begins to starve the engine. This is especially true if your fuel pump is working.

 

Here is an RSV fact for you to consider: If you have at least 2 gallons of gas in your tank, the bike will run perfectly at any speed on direct gravity feed from the tank to the carb input. The ONLY things that can affect this are a defective petcock, crud blocking the petcock screen, clogged fuel filter, or kinked/blocked fuel line. If you have a blocked vent line, it will still run for quite a while, and then you will hear the "whoosh" of air rushing in when you open the tank cap.

 

I suggest your pull the petcock and drain the fuel through that hole. Then after it sits for an hour or two, take a careful look at the bottom quart or so of the fuel you drained out. If you do find water in the bottom, then make sure to drain all four carb bowls AND flush the fuel lines and pump before you put it back together with fresh gas. Water sitting in the bottom of the bowls will cause similar running problems. Note that it is actually important to let the fuel sit for at least an hour - when first drained after any amount of sloshing, the water in the gas will not be particularly visible - more like a mist or milky fog than water droplets.

Goose

Edited August 20, 2014 by V7Goose
added info

[V7Goose]

[snip]

I even tried blowing in the fuel line at the petcock and couldn't get any air to pass into the carbs.. even running..

I am at a loss, this is just weird...

Just wanted to mention that you can never get air to blow into the carb from a fuel line unless the whole system is dry. If there is liquid in the carb bowl, the float valve is forcibly shut - the harder you blow, the tighter the valve is shut.

Goose

[Winddancer]

OK.. here is an update, and what I believe to be progress, but also an added mystery..

drained the fuel tank into a big ole pickle jar, let it sit..no water separation..

re-inspected petcock.. still clean..

put it back together and added new fresh fuel to tank, had also bought a new fuel line so I put that on.. bypassed fuel pump, turned on fuel.. got some flow, but not much, started the bike up, still getting some flow, but really not enough to keep up with the demand I can see it trickle in and stop.. hmmmmm I wondered.. so I went to the right side carb vent hose, and checked to make sure it was not plugged up.. gave a slight blow in it, engine RPM bottomed out to the point of almost dying, but sputtered back in seconds, but when I did that blow I could feel fuel gurgling so I gave a quick suck on the hose and baamm fuel filter filled up in a millisecond and no stayed full as I ran it.. reved it trying to suck down the gas, but it stayed full...

turned it off, let it sit for a while, started it back up, and now we are back to square one, trickle of fuel that couldn't keep up,and it was easier to see it go down this time starting with a full fuel filter..so I went to the left vent hose did the same thing, go the same reaction, fuel filter filled right up..

I have yet to bolt the bike back together so I didn't take it for a test ride. but with all the idling and revving for 20 min the fuel filter stayed full..

so does anyone know why or what blowing/sucking on that line does, and why it corrects my fuel flow??

I think I would look a little funny doing that every time I turned the bike off..

but as of now, that is the only was to get good positive fuel flow..

[Kirby]

Are you 100% sure you haven't got the fuel lines reversed at the pump?

[Prairiehammer]

OK.. here is an update, and what I believe to be progress, but also an added mystery..

drained the fuel tank into a big ole pickle jar, let it sit..no water separation..

re-inspected petcock.. still clean..

put it back together and added new fresh fuel to tank, had also bought a new fuel line so I put that on.. bypassed fuel pump, turned on fuel.. got some flow, but not much, started the bike up, still getting some flow, but really not enough to keep up with the demand I can see it trickle in and stop.. hmmmmm I wondered.. so I went to the right side carb vent hose, and checked to make sure it was not plugged up.. gave a slight blow in it, engine RPM bottomed out to the point of almost dying, but sputtered back in seconds, but when I did that blow I could feel fuel gurgling so I gave a quick suck on the hose and baamm fuel filter filled up in a millisecond and no stayed full as I ran it.. reved it trying to suck down the gas, but it stayed full...

turned it off, let it sit for a while, started it back up, and now we are back to square one, trickle of fuel that couldn't keep up,and it was easier to see it go down this time starting with a full fuel filter..so I went to the left vent hose did the same thing, go the same reaction, fuel filter filled right up..

I have yet to bolt the bike back together so I didn't take it for a test ride. but with all the idling and revving for 20 min the fuel filter stayed full..

so does anyone know why or what blowing/sucking on that line does, and why it corrects my fuel flow??

I think I would look a little funny doing that every time I turned the bike off..

but as of now, that is the only was to get good positive fuel flow..

 

Does the Second Gen have a 'roll-over' valve? It is a one way check valve to prevent fuel from spilling in the case of a laydown.

[Neil86]

Kevin...yes on the rollover valve on the 2nd Gen.

[Neil86]

I would ensure the vent hoses are not pinched by the tank.

[Winddancer]

Fuel pump is disconected and out of the equation..

the vent hose from the top front nipple on the fuel tank is discontected, and although I maybe wrong, that is the line to the rollover valve.

None of the vent or fuel lines have a kink,they all have been pulled out and replaced.

all hoses,filter and fuel are new. and the are just laying/hanging on the bike to ensure there are no kinks and bends.

the only thing that comes to mind is if there is a valve in the carb vent circut to keep fuel from leaking out the carb vent tube, but, when I cleaned the carbs I don't remember seeing anthing like that,it really is just a plastic tube.

I cleaned and removed all I could get at, used cleaner and air hose to blow thru the tiny holes of the carbs.. , but maybe someone who works on these carbs often would know, because I really don't want to pull them and take them apart again if nothing is there, and looking at the schematic of this carb and all its peices I don't see one.

[Neil86]

The tank vent elbow has a very small orifice in it... try blowing (lung power)back through it with cap open.

[Winddancer]

Neil86: I will do that, but, I don't think it is the cause, since I have the gas cap off as I am running these tests just to take any possible vacuume question out of the equation..

and to even take it one step further, I have the carb tune hooked up to monitor the vaccume and changes in carb, and to ensure there is no vacuume leak there..

Edited August 22, 2014 by Winddancer

[V7Goose]

Not seeing a fuel filter fill is not uncommon, and not necessarily a problem. For example, I put an external clear filter on my generator (just gravity feed and only about a 2" drop between tank and carb), and most of the time when it is running I just see a bit of gas spitting into the filter with NO pooled fuel in there at all. But occasionally it will completely fill the filter - no idea why.

 

Since you do not have the fuel pump connected, you have only the weight of the gas to fill the carbs, and nothing allows the air to really bubble up out of the filter into the tank, which would be necessary to fill the filter if the air is not sucked down into the carbs. Therefore, it would seem normal to only be able to see the slight trickle of gas equal to what the engine burns at idle. This is especially true if the filter is not mounted vertically.

 

At this point, you may not have any problem at all. But if you still DO have a fuel feed problem, the most likely suspect would be the neoprene tips on the float needles being damaged from a nasty chemical cleaner. The only brand of cleaner I will use on these carbs is Gumout, as that has proven to me to be safe (and some others, like the old STP cleaner are absolutely NOT safe).

 

Also be certain that the vent lines that run from between the carbs to the front of the air filters are not pinched or kinked - that is real easy to do when installing the carbs. I know you said you can suck through them, but that alone does not prove they are not restricted by pinching or kinking - applying any vacuum or pressure to a soft line like that is totally different than free atmospheric air.

Goose

[Neil86]

Neil86: I will do that, but, I don't think it is the cause, since I have the gas cap off as I am running these tests just to take any possible vacuum question out of the equation..

 

Okay...thought you only had the tank vent hose removed...sorry

[Winddancer]

V7Goose..

I agree with you about the filter, what seems to be happening is, I can start with a full filter, and it will slowly go down as the bike runs, and the new fuel will trickle in as it is suppose to, but, what is happening is the fuel flowing into the filter is less then the fuel flowing out to the carbs and it eventually starts lugging and chugging and dies.

when I start with an empty fuel filter, it does pretty much the same, spits in fuel, but the engine dies out much quicker..

Tomorrow I am going to put everything together and take it out for a spin and see if running at a higher rpm then idle helps draw a steady flow into the carbs, and if not I at least know how to fill the fuel filter and line fast.

when I cleaned the carbs I used Gumout cleaner.. a whole 16oz can..

 

Niel86.. no need to say sorry... I left it out of my latest update..

as sometimes I forget I know what I did, but you all don't unless I say..

[billmac]

have you checked the throttle cables to make sure they are adjusted right. the cable may have been stretched or out of adjustment not allowing the slides to move right. was the grips changed before this started or maybe just came loose. Seen this happen a couple of times and get this same type of behavior. won't hurt to look.

[Neil86]

You mentioned you were testing in with all hoses off to the side, not sure if that applied to the bowl vents too.

 

Its been awhile since I did the valves on my 99...thought I had a pic of air plenum off...don't see it on this computer.

Are the bowl vent hoses going through the hole in the carb frame at the front of the

carbs...pretty sure thats the route...if they are connected passing over the frame

I think the air plenum will pinch them.

[Winddancer]

Well after a few days of putting the bike thru its paces, I can feel confident in saying it is fixed, why, I have no idea..

the last thing that caused a change was blowing in the carb vent tubes, so I may have had some sort of blockage in the tube since I checked and rechecked they wern't pinched..I am thinking I had a spider build a web/nest thing in one of my tubes on another bike long ago, and that maybe what happened here..

but I have put 700 miles on it since I put it all back together and have had good postive fuel flow.

so I want to thank everyone for thier help and suggestions..

I know I would have never looked at that hose if it wasn't suggested.

 

Thank you

Chuck