Desperate for help: Bike starts stuttering after a while - repairs itself by turning engine off and on again

jaffabaffa

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Wow, that's REALLY BAD..

And yes, that would in-deed cause some running issues.

As the pump would run at "key on" and pump till primed/pressurized line,
I don't know if the pump would keep running (there's no build up of pressure) .
It wouldn't hurt the pump(or bike) for a second or two of running. But I'd be quick to turn off the key.

If your old pump primed, and it sounds like it did, you know the wiring is fine.
If you really want to check the new pump, I'd just run 12 volts to it for a second..

The old assembly is most definitly an issue


Thanks for the reply! Off course I'ill thoroughly clean both the tank and fuel pump assembly, and make everything as new again.
 

trepetti

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Hey guys,


Small update.

Today I removed the fuel pump assembly from underneath the tank. This is what I encountered:

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Looks pretty horrendous to me. What do you guys think?

I have rust remover by Tank Cure in the tank right now.

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I'ill leave the rust remover sitting in the tank over night, and will continue working on the bike tomorrow.

I do have another question though.

Can I connect my new fuel pump to the wiring loom, so I can test if its starts to prime when I turn on the ignition? That is without it being in the tank, or being in any fuel for that matter. Is that oké, or would that possibly damage the pump, or confuse the ECU?

Many thanks!
FYI this is no 'small' update. This is MAJOR!
 

jaffabaffa

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There is NO WAY that pump screen would allow enough fuel flow to keep up with demand! When troubleshooting I rank things into:
Obvious
Probable
Possible
Unusual

Your pictures all rank as Obvious. I think you found the issue.

I think so too! I'ill keep you guys updated
 

Gary in NJ

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Not to say I told you so, but I did; August 27, post 4.

We’ve gained a lot of experience on maintaining these aging bikes. If someone with experience tells you something, its usually for good reason. What you removed from your tank is exactly what I expected to see. I’m not surprised, but I am surprised that you went to great lengths to find other problems for something that seemed obvious to many of us.

Once repaired your bike should run without any further fuel starvation.

Now, on to something else.

A lot of that rust likely made its way past the screen and into the fuel rail. It would be prudent to remove and clean the fuel rail. This could save you from having to replace a clogged or damaged fuel injector in the very near future. While the tank is off, you have good access.
 

jaffabaffa

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Hey guys!


So today I cleaned the fuel tank and the fuel pump assembly. I also replaced the fuel pump.

Here are the results:

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After reassembling everything back together again, I stumbled upon a problem. When I filled up the tank, fuel started pouring out of the white-coulered fuel hose nipple (see image below).

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This is only supposed to happen when the fuel pump is running, right? I made sure to assemble everything bake together to exactly as it was before. Did I made a mistake, or is some component of the fuel pump assembly not doing it's job?

Do you guys have any idea?

Really looking forward to your answers!

Many thanks!
 

TownsendsFJR1300

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The line that slips onto the white part is a quick release.

Even with a full tank and line disconnected, it shouldn't leak.

I suspect the seal/o-ring in the LINE perhaps got pinched/crooked when installed..

This, ^^, is assuming the white piece didn't get cracked.

Make sure the fuel tank to pump o-ring is not leaking..
 

jaffabaffa

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Fuel leaking problem solved!

You were right on the money, @TownsendsFJR1300. It was indeed a pinched/crooked o-ring between the upper and lower part of the fuel pump housing.

Pro tip:

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Unfortunately the big o-ring between the fuel pump assembly and the fuel pump has flattened a hardened too much to make a proper seal. I have ordered a new o-ring, but it will most likely take a while to arrive here. It will be either next weekend or the weekend after that before I can continue working on the bike, and test if the initial problem has disappeared.

Will keep you guys updated!
 
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TownsendsFJR1300

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Just a quick note re that tank seal. A member, many moons ago, got stranded with that tank/pump seal leaking (in the US)..

I've replaced my tank several times and once, changed the seal(wasn't leaking) for good measure.
Like you, he couldn't get that seal ASAP. I ended up overnighting my old(but still good) seal to him to get him home...

Moral, especially with the age of our bikes now, change out that seal if you have to pull the pump-Cheap insurance, etc..
 
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