Modern Vespa

So, like most folks I've had issues with filling my Vespa GTS 250ie with fuel. It seems the fuel shutoff system is not fast enough, subsequently the aft part of the scooter gets a nice 92 octane bath. I saw these fuel float balls on e-bay. It seemed like a nice idea to use the floats as a visual indicator as to the fuel level, thereby bypassing the gas station pump shutoff system as a means to determine when to stop filling.

here are the floats, made of high density polyethylene (same material as the plastic fuel storage containers)

here is a view of the floats in action (from vendors web site)

Prior to using the floats, I wanted to make sure they worked and would not mess up the fuel pump and/or the fuel level indicator.


the top of the fuel inlet sits 20 degrees from normal, I purchased an old beatup fuel tank off of a GTS from e-bay for a steal.


the e-bay tank came with fuel cap and fuel level indicator, I fabricated a brace to place the tank into the correct level position


OEM tank cap angle


this hole would house the fuel pump


removing the fuel level indicator


seal the fuel pump hole


add water to determine the volume capacity


pour in water


right at 9.0 liters = 2.4 gallons
ok....now drain and pour in slowly (marking the liter levels and determine when liquid is visible from the tank inlet


pour and mark level at liter intervals


level marks


another level mark view


the first sign of fuel can be seen at the 6.8 liter mark or 1.8 gallon


bottom of fuel tank from fuel cap position


marked position


float diameter =.78 inch


fuel nozzle (that hole is the shutoff sensor, once fuel reaches that position, it should stop flowing)


inside the nozzle, dia = .840 inch


add 15x fuel balls into e-bay tank and fill with water. Unfortunately, I could not see any of the balls while filling and the water overflowed. The problem was the balls were getting trapped in the pockets and behind the fuel level sender unit.

On to Plan B- tether the ball, use tether to provide visual indicator:


stainless steel wire dia = .025 inch


smallest drill bit over 2xdia wire= .064


drill into float ball (one side only)


fish hook wire


insert into float and add knot


seal with fuel resistant sealant


quick check concept


add water to tank and watch for exposed wire to rise


float with wire inserted into tank.

Note the wire was too long, the ball tended to float aft not necessarily making it to the fuel hole, need to shorten the wire


right size wire, about 4 inches in length


float stays in slot, wire rises when in contact with fuel. about .2 liters of volume remain when wire starts to rise


checked remaining water volume with more accurate container

Now for real life test run:


at pump station, inserted pump and starting fueling, got some back spray as the fuel contacted the float, it sprayed back on bike some, so....


I pulled back on the nozzle so I could see the fuel going in, this also necessitated that the sleeve be pulled back with the left hand while fueling, over-riding the vapor recovery system shutoff mechanism, but no spay back and kept the fuel at full speed. once the wire started to rise I shut of the pump


no overflow...


picture of e-bay tank in relative position to the OEM tank


float in baggie stored in pannier, ready for next fueling



Observations and review:
1. It seems the last bit of fueling causes the issue, once fuel reaches the shutoff sensor, it is about too late. The float tether provides sufficient time to react by turning off the pump manually.
2. Fuel tank volume measured did not include the fuel pump volume, so it may be off some.
3. Only fueled once, but the trail run was successful.
4. Fuel is only visible once 6.7 liter mark has been reached
5. stainless steel is immune to gasoline
Enjoy!
Keithm

This seemed like a lot of work. I had issues and posted about it a while ago.

I have a solution to the tank overflow problem....

This solution works perfectly. Like you have noticed, the shut off on the pump seems to kick in a little too late and your scooter gets a fuel bath. All I do it hold this modified funnel in place, put in the hose and start filling. At the time I posted my funnel idea, I had only put in two tanks but both times it over flowed. Since I have been using the funnel, I have about a 50/50 success rate in filling the scooter without over flowing the tank. But with the funnel, it does not matter. If the hose does not shut off in time, the gas will splash up in the funnel, the hose will turn off, and then the gas will drain into the tank and not get on the scooter. Then you lift out the handle and remove the funnel. If gas does splash up into the funnel I wipe it out with paper towel that they have at the pumps with a little water from the windshield cleaning water and the funnel is clean and does not smell of fuel. I have even done a second click to get the tank filled right to the top with ease.

I kept fighting to top the tank off, to get the last drop. Finally I listened to the others on MV and I now stop the pump when I hear the first click........ PROBLEM SOLVED.

.

Sounds like a good fix. I also noticed while I was filling and emptying the e-bay tank that there is lots trapped air within the tank. You may consider rocking abit the scooter after a fill-up, this will burp the air and allow the fuel in your funnel to drop into the tank. If you look at the tank there are a few upper cavities that air can get trapped during a fill-up.
Keithm

Maybe the pumps at my local gas stations are different, but keeping the pump flow at full speed will cause a overflow event. The pump cutoff is not fast enough to keep the fuel from flowing past the tank inlet. Feathering the pump helps, but then it is a game of check level, pump, check level, pump, check level....and so on.
Keithm

The gas that slashes into the funnel is very little and it does drain back into the tank. I have actually added more gas until it clicks again and it has splashed up into the funnel and then drained into the tank. Then I can actually drive more than 10 miles on the first 1/4 tank. The problem with the pumps is that there is bubbles in the fuel coming out of the hose and that is what bubbles out.

I am filling at the slowest possible rate and it is overflowing at the first click not from trying to top it off as others have mentioned. The funnel works for me and has rendered this issue a non event for me. If you get lucky and you fill it up without overflowing. Than great. If you have an overflow, no biggie the funnel catches it. But either way no gas has touched the scooter since.

Wow. Dedication to a solution. Good research. I appreciate your efforts and have marked the thread.

However, I'll share a method that works for me. I fill with one or two bars on the gauge (soon after light comes on). That means I can put in 1.5 gal. without paying attention. The last bit is a slow fill as I nudge the scoot with my knee. That causes some sloshing and I can see the level. When it gets to the bottom of the filler neck, I stop. (If it's a particularly easy-to-control pump, I may squeeze in a few more drops.)

Again, good work, and some interesting observations along the way.

Off topic, but where did you get/what are the panniers you have on your scoot? They look like ammo cans. Are they home made and how did you install? thanks....

Bill,
The panniers and rack are home made:

rear view

front offset view
the step-by-step fabrication is detailed here:
make a Vespa Pannier step-by-step walk thru
All the Best!
Keithm

I never have issues with gas going all over the place when filling my 300. All I do is pay attention to how much gas I'm putting in there. I know that it will always take at least 1.1 gallons of gas at the level I usually fill up at and when I get to that point on the display I just make an extra effort to squeeze the handle just a hair so that gas is barely coming out and the auto shut off always engages soon after and I never get any overflow. Might get some in the cap area once in a while but nothing like you guys are making it sound like ...gasoline bath for the scooter

I had a few extra raw material I did not want to see goto waste. So, I made a few extra floats for MV member distribution who would like to give this a try, at gratis (i.e. free).

materials include stainless steel piano wire, gas immune float balls, and fuel resistant adhesive.

3x trimmed to fit the GTS tank inlet
2x untrimmed, so the member can fiddle with the length of wire, as seen fit. All drilled, wire attached, and adhesive sealed.
If you would like a tank float please shoot a PM with:
1. shipping info.
2. indicate if you would like wire cut for GTS or uncut.
3. US folks only and I do not want to hassle with overseas shipping.
4. MV member in good standing.
Enjoy!
Keithm