Fuel consumption has suddenly got a lot worse

[Xactly 5,437]

1 hour ago, Scootabout said:

Talking of enricheners, my old Burgman AN400Y, with carburetor, apparently had one that functioned by the melting and solidifying of wax. When it was cold the wax was solid, and the enrichener was (somehow) on. Then as the engine heated up the wax melted, thus turning the enrichener off. Doesn't sound very high tech, but it seemed to work. 

Perhaps it was a design pinched from the Suzuki B King? I’m already putting my coat on….😊

[Steve Case 955]

Yeah thats right the burgman did exactly the same thing in winter. Used to lose 5mpg in the cold.

[aquaboy 105]

My other hobbie is boating, E10 petrol just doesn't keep, seems to seperate out in the outboard tank.  As I take the spare fuel can to fill up on the NC  I usual top the bike tank off at the same time with shell V max (E5) or what ever its called.  Both engines run nicer on the premium fuel. Mixed riding its easy to get mid 80s mpg.  and a couple of weeks ago trundling along in traffic around  40 for a few miles I saw 94mpg.  best ever,

[BackMarker 170]

Having been garaged for the past 3 months, I started up the NC750S on the dregs of a tank of E10.

It went first go! (Honda, you see...)

I then rode to the local Esso station, and filled it with their Synergy Supreme 99, which contains no Ethanol, but must still be labelled as E5. It is 20p/litre more than E10, so I won't be doing that very often.

The dash showed 81mpg on a little bimble round the lanes, at 6degC.

It's an exciting life.

 

[Xactly 5,437]

That’s what I always use. My Moto-Guzzi started first prod after a winter lay-up of four months recently. The tank was full of Esso E5 during this period. The fuel doesn’t have the nasty smell of ethanol in it; I believe that here the Esso good stuff has little if any ethanol in it.

[Andy m 23,587]

On 21/01/2023 at 18:40, fj_stuart said:

 This made no difference to the bike's running even during a Scottish winter.

Wait until you go for a spring ride in the Highlands.

 

It's all about dew points. The pressure drop across the orifice depends on the flow and opening. 

 

Worst case is fully open, low RPM, lots of water in the air (or fuel), low air pressure.

 

We had problems with XBR's on the Elefant in 2004 (or 5-6). Not cold, only 3-5 Celsius. However, the hills get higher in southern Germany, it was threatening a thunder storm and an XBR500 outfit needs full throttle quite a lot. They'd be down to walking pace or die completely up hill, then suddenly recover. Difficult to work out what's doing on when it's intermittent until the second one starts doing it at the same time. The solution was a notebook cover taped in place to direct exhaust heat onto the carb.

 

You've got to love FI.

 

Andy

[jeremyr62 2,573]

4 hours ago, Xactly said:

The fuel doesn’t have the nasty smell of ethanol in it

Many alcoholics would take issue with this observation this I expect.

[Blandy199 31]

I did say i would report back once the weather has warmed up a bit.

At long last it has warmed up and yes, as so many of you said it would, fuel consumption is back to normal. I can now comfortably do a week's commuting (240 odd miles) on a tankful. 

I suspect that a lot of this is due to being able to actually see better now the lighter days are with us and therefore carrying a lot more speed through the corners combined with dry roads ecouraging more spirited cornering.

Thanks for all your suggestions.

[Bostedsprocket 213]

I recently installed a de cat front pipe used with the original can, the bike sounds better revs much more freely and is noticeably quicker and smoother off the mark, the only down side is the mpg has suffered slightly, the average mpg used to never be out of the 80's  now its low 70's, if i filled the tank to the brim the first fuel block on the gauge would drop off at around 70-75 miles now its usually between 57-62, its not enough to bother me and is still the most economical motorcycle iv'e ever owned.