Modern Vespa

I've searched here yet can't find anything pertaining to my problem.

Went to fill my Vespa today (2021 GTS 300) and as usual put in the good stuff. Showed all bars full.

Began my ride. One bar disappeared at 35km or so…thought that was strange. Then at 64km, another bar disappears.

Stopped for at a provincial park, enjoyed the day. Time to leave, I drove a few meters and suddenly the low fuel is flashing. Then it goes back to only 3 bars left (when I stopped, there were 5)

Stopped again to check things out. Couldn't find any leaks, I also didn't see anything on the ground when I left my break stop. Put the bike on the stand and gave it a shake, heard fuel sloshing around in there, yet who knows how much!

Thought I'd try for home, again when I started it indicated low fuel, then back to three bars which quickly changed to two, then after 30km, one bar. 10km from home the low fuel light goes on.

What the heck? Made it home yet only did 93km. Usually at 173km I still have at least 2 bars left.

Anyone experience this before? Something wrong with the indicator in the tank, or?…

That sounds like a dodgy connection where the fuel sender connects into the harness.

Check the wiring.

Thought I read somewhere that a faulty fuel sending unit is a common issue. Hopefully you're still under warranty

Thanks, both of you. Such a quick response!

Yes, it is still under warranty. Despite the fact it's a 2021, I bought it new this year as it was last year's stock. Frustrating problem.

Poor little Guido. He doesn't mean to be a problem I'm sure.

Owner of half dozen motorcycles, and I check the fuel meter on none of them because most can't be relied on to be too accurate to be completely honest.

Instead I just reset the trip meter every time I fill up, or look at the odometer, and know roughly when I'll need to fill up again based on that.

Given that your bike is new, if you can get them to take a look under warranty, may as well, but don't be too surprised if it comes back again when out of warranty. No big deal.

The problem of a fluctuating, inaccurate fuel gauge on the Vespa GTS 125 / 300, Date of manufacture (not date of purchase!) in 2021 is known in Europe. Tank sensor is defective, shows significantly less when the tank is full and level is fluctuating/moving over multiple levels. Solution: Tank sensor must be replaced. For the warranty claim, it is helpful if you can document the problem with photos/short video (e.g. after filling up the tank bars in display are not full).

To make it clear: the tank gauge on two-wheelers has a higher inaccuracy than on a car, for example, due to the small tank, the lateral inclination and the acceleration forces. Therefore, the fuel gauge is always an estimate rather than an accurate measurement. The above-mentioned problem with the tank sensor describes an inaccuracy of several levels in the tank display.

Good luck!

Definitely a known issue in the US also. On my 2021 300 HPE the sensor was bad, replaced under warranty. Even after replacement though it still fluctuates a little bit. Usually it's just one segment on the fuel display that will go up or down.

Well it sounds like an ongoing issue.

I will try and take some pictures of the display the next time it happens to document for warranty.

However, I guess the best gauge is watching how far I've gone on each tank.

In everyone's experience, how far can you go on a tank for the GTS 300 HPE?

Three considerations, highway speed; mix of city and highway and just city.

I typically travel at speeds from 70km/hr to 110km/hr, other than when I go into town for fuel.

Thanks!

I get 32km/l when riding in the country and about 28 in the city. Max I've done on a tank is 269km.

That is helpful, thank you. I'll keep track and hope for about the same.

Mode button reset is your friend.
I refill at about 100 miles.

I generally get about 200km before I fill my 2017 GTS Super. Normally put in 6.5 to 7.5 litres. Averaging 3.5 l/100km.

Appreciate the answers regarding average mileage.

Went for another ride yesterday. Filled up first, and turned the key to see the indicator (for what it's worth!) and it 'said' all bars full. Squeezed a bit more in yet no overflow.

At about 70km it said 2 bars, then around 80km the low fuel light came on. I ignored it. Then I noticed it went back to 2 bars. Then at 100km back to low fuel, and I rolled in the garage at 111km and low fuel light.

It was hard to keep going on my ride at one point with such a low fuel mark and no available place to fill up yet I told myself that there was more gas in the tank that it showed so I managed to ignore it, for the most part!

After Guido cooled down I turned the key to check the indicator…3 bars!

At any rate, my dealership knows about the issue now and will check it out when I bring Guido in for first service. Warranty on that is good until 2024 apparently. I'm keeping track of all fill ups and kilometers, more closely than before.

Here's a picture halfway through my ride yesterday. Don't you think Guido looks full of fuel?

Perhaps it would ease your mind to carry a fuel bottle (MSR, etc)?

That's a good idea. Even a litre extra or so would help for peace of mind.

So Guido just came home from the 1000km service. They think it was a wiring issue (as someone recommended here) so hopefully an easy fix, we will see.

Glad to have the engine break in all done! Now, onward for more adventures! Might not be many before the snow settles in…

And this up and down behavior of the fuel gauge has gone?

So far it seems fine. I need to go for another longer ride, so time will tell.