Winter Milage?

[Dan M]

Today the Sport sputtered out at 153.7 miles and took only 4.6 gallons to fill up. I haven't ridden much over the last few months and wonder if 'winter-gas' does evaporate more readily?

 

 

Evaporation is only a factor if you've removed your carbon canister. It is there after all to control evaporative emissions. When the bike is off (no vacuum to the vent valve) the system is essentially closed and nothing can evaporate. This is why some complain of a fuel odor in the garage only after removing the canister.

[docc]

Docc.....

Sputtered out?? Or light came on? It's the 4.6 gals to fill that gets me.

That means you had at least 1/2 gal. of usable gas in there. I put 5.2 gals in once.

Who knows...every one of these things is "unique". I've got a good one. Must have been built before lunch. The paint never flaked, the spring never failed, the relays never failed,

I get decent mileage, .....

(knocking on my desk like Gene Krupa ...I do believe in spooks...I do believe in spooks )

 

The light had been on about ten miles. It sputtered out as in limp to the side of the road and do the tip-slosh-reserve drill.

 

The 4.6 gets me too. It's done this before although it typically runs out at 5.1 or 5.2. With the manual petcock this phenomenon remains a mystery. If it was evaporative loss, the tank would still take the 5.2 gallons.

 

The Sport does get 4 or 5 mpg lower in the cold temps; presumably as the ECU feeds more fuel to the denser air. Runs better too!

I've got the temp sensor mod on my list of more-things-to-do.

[GuzziMoto]

Evaporation is only a factor if you've removed your carbon canister. It is there after all to control evaporative emissions. When the bike is off (no vacuum to the vent valve) the system is essentially closed and nothing can evaporate. This is why some complain of a fuel odor in the garage only after removing the canister.

Not positive about the V11 evaporative system because it's been off the bike so long but most systems are not sealed. There is a in to the carbon canister(s) and an out. The carbon is supposed to trap fuel vapors. If the tank was sealed, on a hot day it could rupture. That would not be enviromentally friendly. I know for sure my Griso had an in and an out to the carbon canister.

[Dan M]

Not positive about the V11 evaporative system because it's been off the bike so long but most systems are not sealed. There is a in to the carbon canister(s) and an out. The carbon is supposed to trap fuel vapors. If the tank was sealed, on a hot day it could rupture. That would not be enviromentally friendly. I know for sure my Griso had an in and an out to the carbon canister.

 

I've seen an accumulation of pressure in many modern fuel tanks on hot days. That's that ffft noise when opening the cap. I haven't seen one rupture though.

I'm not sure I buy that evaporation is the cause for poor mileage. I generaly fill my tank before storage. I live in Chicago where the fuel is blended seasonally. If I fill in mid to late December, I get winter formulated fuel. By late March when I prepare to ride again, and the bike has been sitting in a heated garage for 3 months, the tank is still... full. If evaporation was at such a greater rate than regular gas (which evaporates rather quickly if given the opportunity) as to cause a noticeable drop in fuel economy, then certainly I'd see a loss after 3 or more months.

The complaint here is of far less mileage from a given tank of fuel. If someones tank range is off by 20-30 miles, and it was caused by evaporation, that means around 3/4 gallon has evaporated. That's 3/4 gallon more evaporation than with regular gas. On just one tank full! Just doesn't seem likely.

[GuzziMoto]

I would agree that the poor mileage is not due just to evaporation. Iwould think that is only a small part of it. But the things that help the fuel evaporate at lower temps so your engine can run in cold weather also do not contain the energy that fuel components that do not evaporate as easily contain. So gas formulated for winter driving will not return the fuel mileage that gas formulated for summer driving will. Plus the engine tends to run cooler which contributes to another loss of efficency and thus mileage.

Most of the tanks that build pressure in the sun, in my experience, are non carbon can equipped.

[Ouiji Veck]

Tis a quandry........

All will be reveild this week end I do believe.