Gas problems

[Murph MagicTone]

Hi all, I have a 2011 Sprint GT I bought new back in July. Everything has been great until the last couple of fillups. My gas mileage when from an average of around 41 in mixed city driving to about 29. I haven't been riding any differently. I filled up a second time to make sure and the mileage is still terrible.

A couple of things I noticed:

1. When I open the gas filler cap I no longer get a firm 'throwk' sound. Now there doesn't seem to be much of a seal at all when I open it.

2. I can sometimes smell gas fumes around the filler cap. I first thought it was just spill from filling it up, but now I wonder.

Any thoughts on what could be causing this? Could the seal on the cap have a problem for some reason and could this much gasoline loss be caused by evaporation? Or should I check something else? I wanted to check here before I take it to the dealer.

Thanks in advance.

[jazzafox76]

G'day Murph
Is the bike running rough ? The majority of fuel sold these days is pretty ordinary from my experience. I only use 98 RON for that reason now after having had to clean fuel injectors and renew spark plugs to to fowling etc. I found a short speile from a honda site may pertain to Triumphs since they are both injected..."Pull the vacuum hose off the fuel pressure regulator and ensure it's dry.
If it has fuel in it, the diaphram is torn so you'll have to replace it." I'm sure if you google it you will also find a lot of info....all the best mate.

[KitNYC]

Running higher octane won't prevent fouling. If anything, it will promote it over the long term, as higher octane = harder to burn.

I don't know what sort of sound is expected from a GT's gas cap, but the fuel system works pretty much the same way my RS's does. Turn the key and the fuel pump pressurizes it within the first five seconds or so. If you put your ear to the cap immediately after the pump shuts off, you should be able to hear it if it's losing pressure.

I wonder if you might not have changed your readout from UK gallons to US. Are you looking at the computer, or doing the trip meter vs. gas pump thing?

Cheers,
-Kit

[Murph MagicTone]

Thanks for the replies. I changed from imperial to US gallons as soon as I got it home (learned that tip from this site).

I'll check the pressure and see if I can hear any pressure loss.