When is it full?

[OldGazer]

Got a question about the fuel tank on my '91 VR. The problem is I don't have the owner's manual. I'm rather anal about performance and I'd really like to know what I'm getting for fuel mileage. To do that I need to keep an accurate tally of how many gallons I pump, but I can't do that if I don't know when the tank is actually "Full."

 

For example, I can "fill up," stop pumping, and then watch the fuel level drop slowly. Another squirt and I get the same thing. I know there is an over flow tank involved here, but I have no idea when to stop pumping gas.

 

FWIW, I filled up last night and the bike is getting approximately (Oh how I HATE that word....) 33 MPG around town. This is riding 2-up with a Voyager Kit....

 

Any help will be greatly appreciated

[fordpol]

Keep track of miles travelled gallons of fuel pumped into the tank and divide result is miles per gallon. Or km/100 litres if Canadian :-) Tank capacity has no bearing. More data equals more accurate result. Ken!

[barend]

Keep track of miles traveled gallons of fuel pumped into the tank and divide result is miles per gallon. Or km/100 liters if Canadian :-) Tank capacity has no bearing. More data equals more accurate result. Ken!

 

Yup, what he said!!!

[rumboogy]

I am thinking (scary I know) that what he was really trying to say is how to tell when it is full.

 

What I do is pump until the level no longer goes down, that way you have a standardized way of measuring the amount of fuel put in and it also increases your precision for calculating MPG.

[Flyinfool]

How accuratly the tank is filled has nothing to do with MPG.

The odometer tells you how far you traveled and the pump will tell you how much gas you used. Write both of these numbers down on a piece of paper. after a couple of refills add up the total gallons used and the total miles driven.

 

Miles ÷ gallons = miles per gallon

 

Nothing at all to do with how full the tank was.

 

Now if you are trying to figure out the range of a tank of fuel, just fill it up with as much as will fit. NEVER fill it right to the top unless you will be riding at least 20 miles immediately after filling the tank. If you fill it right to the top then as the gas in the tank expands from the engine heat and/or air temp some may dump out the overflow. I hate dumping gas on the ground.

As far as I know there is no overflow tank, just an over flow.

 

As far as how much to fill it.

Unless I am topping off for a long ride, I just fill to the bottom of the filler neck the first time, but putting as much as possible in there you are really only getting in enough extra gas for about 10 miles at the most. around town that is not an issue, out on the open road where gas stops are few and far between it might matter.

[friesman]

When I want to check mileage I always fill when on the centre stand as you can fill fit to the top and actually see the level on the filler neck that way. when youre on the side stand it seems you have to stand the bike upright to get the fuel down the neck for the last 10% of tank.

 

Any method will work for figuring out mileage as long as you consistently fill it to the same height every time. The reason I like this way is because I can actually see the gas level and it doesnt burp and disappear like it does when on the side stand.

As discussed earlier, i wouldnt fill this way unless leaving immedatily on a ride as you will spill out the overflow as the gas heats up if you dont.

 

Brian

[MiCarl]

As you're getting at, it needs to be refilled to the same point to get an accurate reading how much fuel you actually used.

 

There isn't an overflow tank on the Venture. The tank is full when the fuel level is at the bottom of that collar below the fill cap. I think maybe you're filling into the collar and then waiting while air bleeds out the vent letting gasoline rise around the collar.

 

That collar is meant to leave an air pocket at the top of the bike. The gasoline comes out of the ground and is often cooler than the air temp. As it warms up it will expand. Without an air pocket any expansion would cause gasoline to dump out the vent.

 

So, just fill it to the bottom of the collar. Realistically that collar doesn't hold much fuel so it's not going to impact your numbers much. To be more precise you can do your calculations over multiple tanks.

 

33 is pretty close to what I get on my 89, 2 up pulling trailer. A bit less even at freeway speed.

[Condor]

I just stuff the nozzel in the neck, and when it clicks off I quit pumping. Next time do it again and divide the miles traveled by the gallons. Should give you a good idea of the MPG. Close enough anyway. If your heading out on a trip and want to make sure it's up to max full, top it off on the center stand and ride. On the '83 I'd usually start looking for a station around 150-165 miles. At 150 it'd take 3.0 to 3.2 gallons in the twisties, and 3.8 to 3.9 out on the slab.

[OldGazer]

Maybe I should have been more specific: What does the owner's manual say about how you determine when the fuel tank is actually full?

 

I have the math down, been doing this for as long as I can remember.

[Condor]

Maybe I should have been more specific: What does the owner's manual say about how you determine when the fuel tank is actually full?

 

I have the math down, been doing this for as long as I can remember.

 

OK so you've been around a while. And to answer your question, the manual does not explain how to tell when the tank is full. I guess you can empty the tank and then put 5.3 USgallons in it (manual)...stop pumping... and that's where it should be when it's full.... unless it's very hot or very cold, and that a whole 'nother subject. Since you are already sitting upright, just fill it up to the bottom of the neck and be done with it. BTW 33mpg with the Voyager Kit and two up ain't all that bad.

[OldGazer]

Thanks Condor.

 

Yep, the old girl does pretty good. We did Rolling Thunder this year, and I got awesome (high 40's) mileage running up I-95 doing 65-70.

 

Ride Safe....