My Bike's Struggles with Acceleration and Higher Speeds

[Macka]

OK you guys, you have made me go out into the sunshine and take some pictures.
The filter is the beige coloured plastic piece in the middle.
The red mesh at the bottom is the "strainer".
You can see how the gauge sender is attached to the filter at the top.
It would be near impossible to work around it to use a substitute.
One interesting thing I found was that the new gauge sender unit would only read the bottom half of the tank.
Although it mounts to the same points, the design is different to the original one and it would stay on full for 200+km before it started to move.
I had to remove the tank again and refit the original sender unit.
It is now back to normal.





Macka

 

[Phil Tarman]

Macka, are all three pictures of the new fuel pump?

 

[Macka]

Macka, are all three pictures of the new fuel pump?

No, Phil.
That is the old tank unit (mount/pump/strainer) with the new (inaccurate) sender unit screwed onto it.
Everything was identical except the sender unit.
The beige coloured old filter would originally have been almost white like the new one but has been stained by the fuel.
I did not take a picture of the new one before it went in.
The round part on the RHS of picture one with the black hose attached is the Fuel Pressure Regulator.
I have kept the old unit in case I need a pump or Pressure Reg in the future.
With practice now, I can drain the tank, swap the unit and have the bike running again in about 45 minutes.

Macka

 

[Phil Tarman]

Thanks for the clarification, Macka.

And now for an update: After having the bike 2 1/2 weeks, my dealer has finally decided that the diagnosis I told them was very likely the problem is probably the problem. Their test of the fuel pump showed normal pressure, but instead of flowing 200cc/10 seconds, it only flowed 65cc in 10 seconds. So, they are having the pump over-knighted to them and should get if Friday. I'll miss a nice 400+ mile ride that I had hoped to do with the Motorcycle Sport Touring Association on Friday, but at least I'll be able to ride next week when it's going to be cooler -- temps in the high 70s instead of the low 90s.

 

[Macka]

Thanks for the clarification, Macka.

And now for an update: After having the bike 2 1/2 weeks, my dealer has finally decided that the diagnosis I told them was very likely the problem is probably the problem. Their test of the fuel pump showed normal pressure, but instead of flowing 200cc/10 seconds, it only flowed 65cc in 10 seconds. So, they are having the pump over-knighted to them and should get if Friday. I'll miss a nice 400+ mile ride that I had hoped to do with the Motorcycle Sport Touring Association on Friday, but at least I'll be able to ride next week when it's going to be cooler -- temps in the high 70s instead of the low 90s.

Good luck with that Phil.
I hope it solves your problem.
However there is something to keep in mind: most pump manufacturers will not honour their warranty on a new pump unless the filter is also replaced.
The old pump has probably been weakened by straining hard to push through a partially blocked filter.
This will shorten the life of the new pump and in a few months time you may have the same problem again.
It is not logical to replace the pump and not the filter unless it was replaced in the very recent past and you can prove it.
They work "hand in hand" and no decent mechanic would replace a pump without doing the filter too.

Macka

 

[DirtFlier]

[..So, they are having the pump over-knighted to them and should get if Friday...]

Try as I might, I couldn't envision a fuel pump being tapped on each shoulder by the Queen holding a sword.

All kidding aside, glad you have the problem resolved but now the test will be in the riding.

 

[mikesim]

Good luck with that Phil.
I hope it solves your problem.
However there is something to keep in mind: most pump manufacturers will not honour their warranty on a new pump unless the filter is also replaced.
The old pump has probably been weakened by straining hard to push through a partially blocked filter.
This will shorten the life of the new pump and in a few months time you may have the same problem again.
It is not logical to replace the pump and not the filter unless it was replaced in the very recent past and you can prove it.
They work "hand in hand" and no decent mechanic would replace a pump without doing the filter too.

Macka

Doesn't the new pump come with a new integral filter? I wasn't aware that the NT had a separate, serviceable fuel filter.... am I missing something....?? Alzheimers?

Mike

 

[seagrass]

I expect they will be replacing the pump assembly as supplied by Honda which I believe includes the filter.

The fact that the current pump is supplying the correct pressure but low volume would suggest the current filter is badly blocked and it is a pity that Honda did not use a pump that has a replacement filter available.

Seagrass

 

[DirtFlier]

+1 on the pump not having a separate, removable filter. It reminds me of the throttle bodies and throttle position sensor only being sold as one unit.

Before I bought my NC700X, I checked the parts diagram to see if the throttle position sensor was available as a separate part and it was!

 

[Brillot2000]

Their test of the fuel pump showed normal pressure, but instead of flowing 200cc/10 seconds, it only flowed 65cc in 10 seconds...

There's your problem... The fuel flow is 33% of the specification. I am not surprised that the bike was behaving as it was under certain conditions.

 

[Warren]

So is the filter plugged up just because Phil has over 100K on the NT and it was bound to happen eventually or did he get some bad gas recently that caused the problem ?

 

[Phil Tarman]

I'm pretty sure from looking at the parts diagram that the pump comes with the filter. For $400+ it ought to!

 

[ARKNT]

It might be interesting to have them save the old parts and cut open the old filter for a look see.
Sounds like they did find the smoking gun to your intermittent problem. You should be cruising in style soon.

Brad

 

[mikesim]

I'd be interested to look at the pump if you dissect it to see if you can see the problem.

Mike

 

[junglejim]

Could it be that Phil poured his fuel into his coffee thermos and the coffee into his gas tank????
Phil has gotten some liquids mixed up before - with a bunch of us watching!!!!!

 

[Phil Tarman]

Could it be that Phil poured his fuel into his coffee thermos and the coffee into his gas tank????

One never knows...does one?

 

[Macka]

So is the filter plugged up just because Phil has over 100K on the NT and it was bound to happen eventually or did he get some bad gas recently that caused the problem ?

I had my first symptom over a year ago with about 85,oookm on the clock.
It then did not show any symptom for another 2,oookm.
Over the next 1000km or so it played up 2 more times.
The final straw was in the last 10km to home of a 1500km trip.
It had been perfect all day on the highway but when I hit the suburbs it suddenly would not go over 70kph.
The tank unit was replaced at just under 89,oookm and has been great since then at up to 140kph.
The filter was virtually completely blocked at 89,oookm (55,ooo miles).
Despite what the oil companies claim, our fuel in Oz is dirty.
In my business I replace EFI filters on cars regularly and often find them very dirty/clogged well before the recommended scheduled replacement time.
If you leave the clogged filter in place too long it eventually kills the pump resulting in a break-down.
Any experienced mechanic will tell you that, it is not just a sales pitch. It actually saves you inconvenience and money on pump cost and repeat labour down the track.
I usually recommend to my customers that the filter be replaced every 40,oookm instead of 80,ooo-100,oookm as recommended by the car manufacturer.
If a replacement filter WAS available for the NT I would have done it at 40,oookm.

Macka

 

[Phil Tarman]

I went by my dealer today to see what was going on. I had expected them to get the new fuel pump on Friday and get it installed either Friday or today. But it turns out that Honda can't overnight fuel pumps because they contain hazardous materials. That surprised me and I was told that they test them after manufacture, so they've got fuel in them. They should have it in the next couple of days and promised they'd get it installed the day it arrives.

We're into Week 4 with this now.

 

[Macka]

I don't believe that story Phil. I had mine air freighted by Partzilla to Australia. Genuine Honda unit in Honda box.


Macka

 

[Brillot2000]

I went by my dealer today to see what was going on. I had expected them to get the new fuel pump on Friday and get it installed either Friday or today. But it turns out that Honda can't overnight fuel pumps because they contain hazardous materials. That surprised me and I was told that they test them after manufacture, so they've got fuel in them. They should have it in the next couple of days and promised they'd get it installed the day it arrives.

We're into Week 4 with this now.

Well, it was your denial that the fuel pump was the cause of this issue and lead to taking this long to resolve. If you accepted the simple fact the pump was the root cause of your woes and cracked open your wallet it would have worked out a lot sooner.

I had a fuel pump go out on me on my ST1300 many years ago. It was intermittent at times and would have caused the engine to surge at random instances. I eventually figured it out and ordered a replacement and installed it myself. The full retail for it was about $500, I ordered it online and managed to get it for about $350 and $6 for the gasket. If I took the bike to the dealer, it could have been over a $700 repair bill.