Fuel Pump Replacement

[Craigmri]

OK amigos, thought being a newbie 'round these parts I would try and contribute something. Just replaced my fuel pump in my 2011 NT700V US spec. 6,100 miles.

Why you may ask? Seems the bike when cold runs perfectly. After the entire engine and fuel load gets heat soaked the bike wont take much throttle. You have to feather the throttle to try and pick-up any speed. This was repeatable. Also, noticable in the fuel tank with cap open you can see some surface rust visable. I knew I had to clean up the tank with Evapo-rust.

I figured, if the tank is coming off and I'm pulling the pump assembly, I'm replacing the pump and regulator pro-actively for this runability issue.

The evapo-rust cleaning went well and I got the tank pretty clean and rust free. The fuel pump screens shocked me however. No wonder the bike had issues! I still replaced the pump and screen.

Overall not a difficult job honestly. Used Quantum Fuel Systems for my pump kit www.highflowfuel.com

Is the powder from the rust condition in the tank??

Craig

 

[mikesim]

Wow! You really had a mess there! That powder could be only rust particles but it also looks like it is very possible that at some time the bike managed to ingest a load of bad gas. Rust (iron oxide) is paramagnetic. That is it still retains some magnetic affinity although not as strong. Take a strong magnet and run it through the powder residue. If any clings to the magnet, you can be reasonably certain that it is/was rust.

Mike

 

[Craigmri]

Wow! You really had a mess there! That powder could be only rust particles but it also looks like it is very possible that at some time the bike managed to ingest a load of bad gas. Rust (iron oxide) is paramagnetic. That is it still retains some magnetic affinity although not as strong. Take a strong magnet and run it through the powder residue. If any clings to the magnet, you can be reasonably certain that it is/was rust.

Mike

Good idea! Since I still have the material on the towel I tried this Mike....The powder doesn't appear ferromagnetic. The flakes of rust however are. You could be onto something with bad gas at some time.

Craig

 

[Phil Tarman]

Craig, my first bike was running like that after about 125,000 miles. I felt like it was a fuel pump, but my mechanic checked a lot of other things first. He finally did a flow and pressure check on the pump. Pressure was OK, but the flow was way less than half of the specified amount. He replaced the pump and it was running fine when I traded it for NT#2 at 139,000 miles.

 

[harryhendo]

Wow, that's a lot of cruft in that fuel circuit. It really looks like sand or dirt to me, not rust.

I'm wondering if you think a fuel filter (which is not fitted on the NT) would have kept this problem from occurring? My 1987 R80 has a fuel filter on each carb fuel line, but the NT doesn't have any filter.

 

[Craigmri]

Wow, that's a lot of cruft in that fuel circuit. It really looks like sand or dirt to me, not rust.

I'm wondering if you think a fuel filter (which is not fitted on the NT) would have kept this problem from occurring? My 1987 R80 has a fuel filter on each carb fuel line, but the NT doesn't have any filter.

Harry, The orange rough sponge and the screen are directly exposed to the open gas tank. Its the first line of defense. It was my understanding that the white body of the pump assembly is the actual filter but dont hold me to that.

The powder is much much finer than sand. More like a flour consistency.

Craig

 

[harryhendo]

Oh, I see that. So the pump assembly is just sitting in the tank of gas, and it sips the fuel through the bottom of the assembly, through the orange sponge and screen. There's no opportunity for a fuel filter, since there is no actual fuel line running anywhere (except, ultimately, from the top of the pump to the fuel injectors).
I don't think the white body has any filter in it, but I could be wrong there too...
There's no maintenance schedule for the fuel system, so it seems that Honda didn't expect the condition you experienced.

 

[Craigmri]

Oh, I see that. So the pump assembly is just sitting in the tank of gas, and it sips the fuel through the bottom of the assembly, through the orange sponge and screen. There's no opportunity for a fuel filter, since there is no actual fuel line running anywhere (except, ultimately, from the top of the pump to the fuel injectors).
I don't think the white body has any filter in it, but I could be wrong there too...
There's no maintenance schedule for the fuel system, so it seems that Honda didn't expect the condition you experienced.

I suppose one could install an inline filter under the tank between the tank fuel pump line and the fuel injection system.

Craig

 

[ARKNT]

You had a bunch of crap in there.
Adding a fuel filter downstream would not likely help in your situation. Like Phil said with his issue, fuel pressure is fine but flow is low. Your pump assembly in the tank could not pump enough fuel, so adding a filter downstream it still could not pump enough fuel.
Now it may keep the stuff out of the injectors better.

Brad

 

[mikesim]

Good idea! Since I still have the material on the towel I tried this Mike....The powder doesn't appear ferromagnetic. The flakes of rust however are. You could be onto something with bad gas at some time.

Craig

That's kinda what I suspected. Now that you've got the fuel system cleaned out, you should be good to go. I wouldn't toss the old pump just yet as it may still be serviceable once cleaned up. You can keep it for a spare.

Mike

 

[nunyet]

I had to replace mine a few weeks after buying the bike 3 years ago. 3100 miles. . The filter got clogged when I refueled the first empty tank and stirred up some gunk. Bike had been sitting and ran fine until i did that, then the filter got clogged and it would not run when the throttle was opened past idle.

For what it's worth, my pump assembly itself was crumbling due to age or poor materials. something like that. The insulation for the wiring, the flexible pickup hose, and some other plastic items were turning to dust; they broke apart in my hands as i removed the unit.

 

[ST1100Y]

For what it's worth, my pump assembly itself was crumbling due to age or poor materials. something like that.

I rather suspect some creepy stuff in the fuel, ethanol, low/no quality fuel additives, something like that.

Just another reason I stick to (well frequented) brand stations and premium grade fuel...

Some ADV guys using fabric filter inserts stuffed down the tank neck while abroad, as you never know what you'll get when refueling at a station with a mud-hut as store...

 

[Phil Tarman]

In the "olden" days of my father's youth pilots used a chamois to filter gas. It would still work.

 

[ST1100Y]

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