Fuel tank capacity and float

[peperino]

Hey

As you may know, the bike tank capacity is not really the advertised, while every spec sheet you see will tell you that the bike has a 16L (4.2gallons) tank, in reality its capacity is 14L (3.7gallons).

Also, the fuel meter is not remotely accurate. In part this is for the way the fuel pump works, it needs to be soaked in fuel to avoid damage, so my guess is that Zongshen deliberately sets the indicator very pesimistic. That way you would refuel before you really need it and the tank would always have some fuel for the pump.

In my tests, when the fuel warning light blinks, you have only consumed about 7-8L (1.8-2.1 gallons) of fuel, so you have a lot of fuel remaining.

As my bike is carburated, no fuel pump involved, I decided to correct this indicator. To fix it, the idea is to take the tank off, remove the fuel float and bend it so it sits lower in the tank.

I think EFI users should also fix it so its not THAT pesimistic and a little more realistic, but just taking care of not draining the entiry tank when riding the bike.

I've made a step by step procedure, it is in spanish but you can easily google translate it (or ask me anything)

https://coltermoto.wordpress.com/tri...ible-flotante/

[Weldangrind]

Originally Posted by peperino

As my bike is carburated, no fuel pump involved, I decided to correct this indicator. To fix it, the idea is to take the tank off, remove the fuel float and bend it so it sits lower in the tank.

If I had the carbureted version, I'd do the same thing. If I had the FI version, I'd leave it alone.

[peperino]

Originally Posted by Weldangrind

If I had the carbureted version, I'd do the same thing. If I had the FI version, I'd leave it alone.

Why.
Do you really think that the fuel pump needs THAT much fuel to work? We are talking half a tank here

[detours]

Excellent write-up! I intend to try this at my next valve adjustment.

[peperino]

Originally Posted by detours

Excellent write-up! I intend to try this at my next valve adjustment.

Feel free to grab the pictures and make a english step by step (or translate mine, whatever is easier for you)

[Weldangrind]

Originally Posted by peperino

Why.
Do you really think that the fuel pump needs THAT much fuel to work? We are talking half a tank here

No, I don't think the pump needs that much fuel to function. I just think that more fuel for cooling is a good thing. I would simply get used to the range that is indicated by the gauge.

[peperino]

Originally Posted by Weldangrind

No, I don't think the pump needs that much fuel to function. I just think that more fuel for cooling is a good thing. I would simply get used to the range that is indicated by the gauge.

I understand.
Unfortunately you would be losing a lot of mileage if you refuel as soon as the indicator blinks

[SpudRider]

Thanks for posting a thread here on this excellent topic.

[peperino]

Ok so, I refueled 3L (+ 2.5 that were already in the tank) and the light didn't blink but I also didn't have any bars in the indicator. So far so good, but I rode 10km and it started blinking again.

I think I'm gonna lower a little bit more so it blinks when you really are low on fuel, the idea is that it blinks when there's about 3L left, just about to hit reserve (reserve is about 2-2.5L.

[peperino]

I'm thinking changing the float height to 30mm now

[keithmaine]

Very good info.

[pepelepua]

Great Job!
I supposed the problem was the gauge and my intention was to correct it with some resistors but you save me a lot of time with your post, the problem is totally mechanical !!!
Now you should see what happens in the full part of the gauge, maybe you´ll have a full indication until the middle of the tank, anycase, I prefer to have accuracy at the bottom part so I´ll do the mod soon.
So many thanks for posting.
Maybe we could meet sometime in Buenos Aires jaja!

Aguante la Ingeniería Argenta!

[peperino]

Originally Posted by pepelepua

Great Job!
I supposed the problem was the gauge and my intention was to correct it with some resistors but you save me a lot of time with your post, the problem is totally mechanical !!!
Now you should see what happens in the full part of the gauge, maybe you´ll have a full indication until the middle of the tank, anycase, I prefer to have accuracy at the bottom part so I´ll do the mod soon.
So many thanks for posting.
Maybe we could meet sometime in Buenos Aires jaja!
Aguante la Ingeniería Argenta!

Yes, now comes the fine tuning, I need to find what float height works better for me

[rtking]

Thanks for the excellent tutorial. (I'll have to translate, but the photos were great and I see exactly what needs to be done.) Looking forward to the final recommended height of the arm.

FWIW, I usually don't rely on the fuel gauge and, instead, look into the tank before each ride, and I check how many miles I've put on the current tank through the odometer / trip meter. I find that the "manual" method is more accurate. I guess it's a non-issue anyway since the bike will easily cover 3 hours of riding on one fill-up, but I'm ready to stretch my legs (and/or pee) after 2 hours.

[peperino]

Originally Posted by rtking

Thanks for the excellent tutorial. (I'll have to translate, but the photos were great and I see exactly what needs to be done.) Looking forward to the final recommended height of the arm.
FWIW, I usually don't rely on the fuel gauge and, instead, look into the tank before each ride, and I check how many miles I've put on the current tank through the odometer / trip meter. I find that the "manual" method is more accurate. I guess it's a non-issue anyway since the bike will easily cover 3 hours of riding on one fill-up, but I'm ready to stretch my legs (and/or pee) after 2 hours.

Thats a very wise method keeping track your mileage, I also use it. My problem with the fuel gauge is that after consuming half a tank, I have a stupid light blinking at me for no real reason. That's basically why I wanted to fix it, not because I really needed the gauge