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Discussion Starter #1
After a few minutes on the highway I bog out and have to pull off as it dies. Its acts exactly like Im out of gas, but Im not. After shutting it off, it runs fine for a while then it does this over again. Im hearing a clicking sound from the tank possibly. I am getting a lot of backfire when this happens.

I have been able to ride around the city with no issues, as soon as I hit the highway this happens.

It is not draining the battery or acting funny at the gauges or headlight. The bike has a new regulator and spark plugs.

It has the 2-1 DND exhaust conversion which runs great, so far without jetting, at all RPMs.

I recently purchased my bike from its original owner with 14,500 miles. It is a near mint, all original bike. The only mods are the 2-1 exhaust.


Im hoping Ducvet or anyone can help...thanks guys!
 

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On the supersports the fuel pump is on full time, see if you hear it cutting out. unlike a injected bike this pump is on 100% when running.
make sure the tank is getting air to replace the fuel used or it will not get fuel, this happens when the air line into the tank is pinched off, possibly a check valve installed backwards. make sure you can blow air into the tank but not out.

Check that you do not have a clogged fuel filter inside the tank or that the gas tank was sealed with a coating like por-15 or kreeme. If something is plugging the fuel exit then you will starve the bike under steady full acceleration. go after the fuel starvation first and if nothing shows up look at spark which is less likely.
 

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Discussion Starter #3
On the supersports the fuel pump is on full time, see if you hear it cutting out. unlike a injected bike this pump is on 100% when running.
make sure the tank is getting air to replace the fuel used or it will not get fuel, this happens when the air line into the tank is pinched off, possibly a check valve installed backwards. make sure you can blow air into the tank but not out.

Check that you do not have a clogged fuel filter inside the tank or that the gas tank was sealed with a coating like por-15 or kreeme. If something is plugging the fuel exit then you will starve the bike under steady full acceleration. go after the fuel starvation first and if nothing shows up look at spark which is less likely.
Thank you Ducvet! I really appreciate your help. That's good to know about the fuel pump. Ill start by checking these things and let you know what I find.
 

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Discussion Starter #4 (Edited)
On the supersports the fuel pump is on full time, see if you hear it cutting out. unlike a injected bike this pump is on 100% when running.
make sure the tank is getting air to replace the fuel used or it will not get fuel, this happens when the air line into the tank is pinched off, possibly a check valve installed backwards. make sure you can blow air into the tank but not out.

Check that you do not have a clogged fuel filter inside the tank or that the gas tank was sealed with a coating like por-15 or kreeme. If something is plugging the fuel exit then you will starve the bike under steady full acceleration. go after the fuel starvation first and if nothing shows up look at spark which is less likely.

Before I bought the bike the carbs needed work...it was leaking fuel from the carbs the first day I looked at it. A mechanic from a local bike shop added an external fuel filter with new lines and cleaned out the carbs, then it drove fine and is not leaking fuel at all.

I have driven this bike for a hundred miles before this started happening. Ive had it near 100mph once with no issues. I have driven it on the highway a couple of times prior to this happening and Ive done some twisties at a park for extended periods with no issues.

Heres what I found so far:

+++I am hearing a lot of clicking from the tank area or under it, when it bogs out. Im also hearing a click when I first drive off that Im not sure Ive ever heard before. It sounded like an old school clock ticking once per second, at a stop light today.

When I blow air into the tank, through the check valve, I can hear air going into the tank and I can hear it coming back out of the cap/carrier at the same time. When I put my hand over the cap it quiets the tiny amount of escaping air.

(I restored the entire fuel cap weeks ago, it had sludge inside the lock mechanism. Since that cleaning it closes flush and functions much better. I have not checked the green carrier gasket yet, but I will soon. This is the tank that leaks when propped up that we talked about).

When I blow back into the check valve, I can blow air out of the tank. I can hear air coming out of the other end of the tube at the ground if I cover it with my finger then remove it...then I can hear it releasing. I have to blow hard for a tiny amount of air to come out.

When I turn the key on, the fuel pump stays running, I gave it about 30 seconds a couple of times and it didn't change in pitch or stop. It did start with a higher pitch the first time, then it settled and ran steady. Is there a way to check this as Im stalling out? Do they click when they go out?

I was afraid to look, but I took a flashlight to the tank. It is slightly discolored in spots with very small amounts of rust around the fittings. Overall not as bad as I thought. Im not seeing debris.
 

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And if your mechanic added a external fuel filter you now have 2 fuel filters, it is possible the added restriction is not helping. If you are not getting anything in the external filter remove it temporarily and see if it improves. You can decide later which one you want to keep but I will tell you that carby fuel pumps are low pressure and I do not change the oem filter often at all maybe once in 20,000-30,000 miles where a fuel injected filter gets changed every 7,000-12,000.

I would chase the clicking to see if it is in the tank (pump) or under the tank. First make sure both battery terminals are tight at the battery, look for signs of arcing. The noise could be the pump working hard as RockAz said other than that there should be nothing making that noise. Check for exhaust leaks at the heads, make sure the head nuts do not spin with your fingers. Listen carefully to the alternator cover, flywheels did fall off/come loose in this era so make sure you do not see the flywheel wobbling in the timing window.
 

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I once chased a similar problem on my bike, it turned out the ring terminal on the positive battery lead for the harness [under the red cap] had fractured and was making intermittant contact. The clicking was the pump relay turning on and off. You may also want to check/substitute the relay and if it has the original fuse in it, I've seen the fuse wire break inside and only with really close inspection could you tell it was broken.
 

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Discussion Starter #8
Yes, it does sound like a clogged fuel filter and probably pick up screen. Fuel pump is working hard, better open it up.
Thanks RockAZ! Ive seen a post on here somewhere showing the filter removal...that can be done from the top correct? Where is the pick up screen? Im not seeing it in my tank pic in the work manual.
 

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Discussion Starter #9 (Edited)
I once chased a similar problem on my bike, it turned out the ring terminal on the positive battery lead for the harness [under the red cap] had fractured and was making intermittant contact. The clicking was the pump relay turning on and off. You may also want to check/substitute the relay and if it has the original fuse in it, I've seen the fuse wire break inside and only with really close inspection could you tell it was broken.
Thanks wdietz! Ill check these things for sure. Is the pump relay under the tank?
 

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Discussion Starter #10
And if your mechanic added a external fuel filter you now have 2 fuel filters, it is possible the added restriction is not helping. If you are not getting anything in the external filter remove it temporarily and see if it improves. You can decide later which one you want to keep but I will tell you that carby fuel pumps are low pressure and I do not change the oem filter often at all maybe once in 20,000-30,000 miles where a fuel injected filter gets changed every 7,000-12,000.

I would chase the clicking to see if it is in the tank (pump) or under the tank. First make sure both battery terminals are tight at the battery, look for signs of arcing. The noise could be the pump working hard as RockAz said other than that there should be nothing making that noise. Check for exhaust leaks at the heads, make sure the head nuts do not spin with your fingers. Listen carefully to the alternator cover, flywheels did fall off/come loose in this era so make sure you do not see the flywheel wobbling in the timing window.

Thanks again Ducvet and all of you guys! I cant tell you how much I appreciate this help on this forum. Im pretty sure my connections are good but Ill check again. The clicking really sounded like it was coming from the inside of the tank...which I think was the pump. It didn't sound like it was coming from the engine or alternator flywheel but that is also great to know and Ill check both that and my exhaust. I forgot to look at the new filter for debris and I will try removing it.
 

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Discussion Starter #11
Ive been searching with no luck. I thought I saw a post on here showing how to remove the fuel filter from inside the tank. Does anyone know where this post is?

Thanks!
 

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I think there are a couple of posts, and I did find a YouTube video once. It's pretty straight forward, run all the gas out of the tank by removing either the external filter (during Ducvets test) or the hose after the "Y" connector and run it into a gas can by flipping the key on without starting it.

Get the cap off, mind the tiny socket head screws and don't back them all the way out if you can help it.

The filter can be seen easily once you have that out of the way. The pump is snapped into a pair of metal clips, have to loosen the hose clamps. The pick up filter "screen" is snapped into the bottom of the pump.

It's a good time to really look close at the condition of the interior paint - and the submersed hoses. I would go ahead and replace the hoses with the right type since it's so old, and the filter sock too.

Putting the O-ring back on with the little screws can be frustrating but take it slow doing only a little bit at a time with small plastic tools as well as a little bit of lube (I used K&N filter lube because I had some).
 

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Discussion Starter #14 (Edited)
If you are still having issues with the disassembly, I can take some photos tomorrow. I got mine apart at the moment.
That would be great Lelebebbel! I wont be able to do this until the weekend. I really appreciate it. Ive never worked in a gas tank.

Im also confused as to what parts I would need. Ill research a bunch. I know I need gas friendly hoses.

Thanks!
 

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Discussion Starter #15
I think there are a couple of posts, and I did find a YouTube video once. It's pretty straight forward, run all the gas out of the tank by removing either the external filter (during Ducvets test) or the hose after the "Y" connector and run it into a gas can by flipping the key on without starting it.

Get the cap off, mind the tiny socket head screws and don't back them all the way out if you can help it.

The filter can be seen easily once you have that out of the way. The pump is snapped into a pair of metal clips, have to loosen the hose clamps. The pick up filter "screen" is snapped into the bottom of the pump.

It's a good time to really look close at the condition of the interior paint - and the submersed hoses. I would go ahead and replace the hoses with the right type since it's so old, and the filter sock too.

Putting the O-ring back on with the little screws can be frustrating but take it slow doing only a little bit at a time with small plastic tools as well as a little bit of lube (I used K&N filter lube because I had some).
Once again thanks for the great info RockAZ! It makes me feel a lot better working on my first Ducati, with you guys helping. I love working on bikes and I don't want to take this to a shop.

Im guessing this is going to be a tank rebuild? How does the pump come out after I remove the clips? Please don't say through the bottom...

Any tips on where to get the parts (Omaha)? and what parts I need would be great.

There were some corrosion spots inside the tank. Im sure compared to a new tank, it looks bad. I was expecting worse though, like flaking or bad rust. Im still trying to wrap my head around rusty clamps inside a tank that is full of fuel feed items....wow.

Ill dig into the sand in my tank this weekend.
 

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Discussion Starter #17
I know if they were an issue, Ducvet would have mentioned it, but Im really surprised fuel pumps don't go out more often since they run all the time...especially these older ones that have sat for years.
 

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Discussion Starter #18
It's a good time to really look close at the condition of the interior paint - and the submersed hoses. I would go ahead and replace the hoses with the right type since it's so old, and the filter sock too.
What then if its bad? Ill take pics to show you.
 

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Don't worry too much, old Ducatis are both simple and sturdy. That external filter looks fine based on the color but maybe it is a little restrictive (ie: designed for 14-16psi instead of 2-3psi pressure) for use on a racetrack or the way you ride, so if it's clogged or too restrictive you can replace it for less than two bucks with a larger generic inline one from any auto parts store.

Fuel pumps on the these old girls only need about 3psi to get the game on, not much will mess them up since they are such low power - as long as sticky or crunchy stuff doesn't get into the system they will last longer than my heart with my love of cheese and pasta.

But rust flakes are bad, that is what you are looking for. So, take some pics once you have it opened, don't smoke while you are doing it!
 

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Once you have the gas cap assembly out the hole in the tank is surprisingly large, easy enough to put one hand in with a stubby short phillips or nut driver and unscrew the hoses clamps to yank the tiny pump out. You will see, I have old school cell phone chargers that are larger than the pump.

Clips? Um, thin "U" shaped pieces of metal that a round barrel shaped pump fit into with a mild amount of pressure?

See the loose rust flakes in the bottom of the tank looking like the rotting fender on your great grandads Model T discarded out in the south 40 acres of his farm? Yeah, you got some more work to do so see what you've got first before digging into what is involved in fixing that kind of problem. Spots of ugly rust on the walls of the tank are sadly not too unusual and eventually they will be a problem but that could be many thousands of miles down the road for you. If the bike has been ridden in the last five years, you likely have nothing to be concerned about. It is a very good sign that the previous owner put that external filter on, they knew what they were doing, and yes I currently have two filters on one bike and the other has no in tank filter anymore - just the external one I can easily see when it needs changed. They both have new pick up screens on the pumps.

So something seems to be clicking inside the tank, you have potential gas delivery symptoms - don't delay finding out the cause of that noise, those are not normal.
 
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