Thanks for answer Pleiades. All of the reasons you mention make a bit of sense.

Although I have been riding in almost same conditions before for example in Kazakhstan and in SE-Asia. And although somehow variable fuel consumption in those places too the bike have never been using this much.

Have to add that the last 2-3 tanks the fuel consumption have been slightly better as I have been averaging 22,2 and 23,1 km pr liter. Strangely as the conditions are the same and my riding style and speed are the same.

The breather hose in the tank do spill out fuel if the tank is filled up completely just after riding and when the engine is hot. I have never noticed that fuel is spilled during riding though...is that reall so that this can happen? How to notice/observere this?

Compared to SE-Asia the fan isnt kickin in much here in Oz. In SE-Asia, especiallyIndonesia where the average speed was 40-50 kms/h it was running more ir less all the time. Here in Oz its very rarely running, so thats not a good explanation.

Can engine temprature have something to say for fuel consumption? I changed coolant in Darwin before starting the Australian leg and used the do called "engine ice". Its supposed to reduce the engine temprature. Although - it must be rather bad stuff as it has been boiling a ccouple of times the last days.

It will be interesting do see ifits any change after the 100 000 kms service in Perth.

This is interesting. "Engine Ice" I believe is similar to "Water Wetter" and is a corrosion inhibitor and water pump lubrication additive, and not an antifreeze; it contains no ethylene glycol. It is disign for race bike/cars where ethylene glycol coolants are not allowed due to their toxicity. Effectively with this in the cooling system you are running pure water.

Water has a much lower boiling point than a water/glycol mix, which may explain your boiling issues. Pure water boils at 109C at 8psi (typical in a pressurised cooling system), whereas as 50% glycol/water mix will boil at 120C at 8psi. The XT's fan cuts in at 102C and the temperature warning light comes on at 110C, which is after a pure water mix will have started boiling! The cooling system on the XT is designed to and will only work properly with at least a 33% glycol mix.

The reason they claim "cooler running" with Engine Ice or Water Wetter is that pure water has a higher specific heat capacity (better at storing and transfering heat energy) than a glycol mix. In other words, with Engine Ice in the cooling system it will cool more efficiently within it's operating range of 4C to 100C, but doesn't work above 100C as it starts to boil at atmospheric pressure. A glycol mix, while slightly less efficient at storing/transfering heat at 50% has an operating range of -30C to 110C at atmospheric pressure.

Engine Ice/Water Wetter will also slow down warm up times and can cause the thermostat to delay opening, which mens the engine is running outside it's temperature rang efor peak efficiency? As I mentioned, the XT cooling system components and fuel injection parameters are match to the properties of a glycol-based coolant.

I think you may well notice a difference going back to standard coolant...

Thanks again Pleiades for your reply and sharing your very accurate knowledge about this subject.
Shouldnt have listened to those Aussie guys in Darwin then. Really strange that they didnt know better by the way....
Will definetively go back to normal coolant again asap.

Hi Snakeboy, I live in Oz on the east coast, ride a 2012 z, have 15/48 gearing, use 95ron , have both kev mods,air filter, leo vince pipes, etc. and riding on a long trip averaging 100kph get almost exactly 400kms before the reserve starts flashing. Maybe it's the aussie fuel that makes the difference. Just a thought.
Brad

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Is the aussie fuel any different than other fuel?

I have used 95 fuel mostly but some of the more remote places between Darwin and Perth have only 91, so have had that 3-4 times.

Anyhow - when you say youre getting 400 kms before reserve starts, is those 400 km on the ODO/trip on your bike or on GPS?

If youre riding with 15/48 your ODO/trip will be faaaar out. More than 10 % I think....

Now my bike has definetively changed to the worse when it comes to fuel consumption. I have now had it served - 100 000 kms - valves checked and fine within specs, new oil and filter, newsparkplug, cleaned airfilter etc etc. Had a run of 1500 kms and more than 3 tanks now and the fuel consumption is around 20 kms of one litre. I have been riding in outside tempratures of 18-25 so not that hot as before.
I even changed rear sprocket at 90 k kms and went down one tooth to 47. Still this increased fuel consumption.

Its such a pity and a shame. This was one of the best features of this bike, especially for my use as an overlander bike - namely the relatively low fuel consumption and thus long range. Now the Tenere uses more fuel than my last bike a Triumph Tiger 955i - if I rode it around 90 kms an hour with panniers etc. And that bike which was a lot heavier and had more than twice the power of the Tenere. The old carburated and heavier 600 Transalp that I had long time ago was also using less fuel.

The boiling coolant issue I had was because I had a radiator cap that wasnt working. Its changed now of course but that had nothing to do with high fuel consumption.

If one google "increased fuel consumption" one can find answers such as bad/sluggish oxygen sensor, defective coolant sensor, lower compression, defective thermostat (mine works ok according to the garage who performed 100 k kms service) or can one of the Kev mods fail in a way that increases the fuel consumption?

Brakes are not hanging, tyres are new and have correct pressure.

To be more precise - before the service I had done at 72 k kms and add that the bike was very little in use the two months before that service I got 24-25 kms pr litre of fuel. Best recorded tank was 615 kms and filled up 22,7 litre which gives more than 27 kms a litre.
Nowadays I seem to get only around 20-21 kms pr litre. Had one tank that I got only 19 kms pr litre.

I am overlanding and the bike is loaded, but it has been like that all the way. I am riding at 90-95 kms an hour maximum, sometimes slower. No hard throttling no hard accelrations. Gentle and careful riding.

Any ideas guys?

Yes you're right. My readings are from my ODO and I know that at 100kph my speedo reads 110kph.
So, I get 400 k's before reserve according to my inaccurate ODO. Or 500 k's for 23 litres equating to 21.74 kpl on a recent run. So factor in the difference of 10% or divide by 11 and I'm really only getting 19.77 kpl, similar or worse than you. And I thought I was getting great economy.
Anyway I wouldnt be too concerned, my mates KTM640 Adventure and Aprilia 650 Pegaso get less economy than my tenna. Maybe it's aussie fuel after all? Safe travels.

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Yeas the fuel consume you describe now is similar to what I have experienced since a while back. Problem is that I got a much lesser fuel consumption all the time from I bought the bike - it had 13 k kms on the ODO - up until 72 k kms.
And the mystery is I havent changed anything since that can explaine this increased fuel consumption. My riding style is the same, my speed is the same, the weight on the bike is the same, even changed the rear sprocket to one tooth less but without any noticeable difference.

Before 72 k kms - 24-25 kms pr litre, after 20-21 kms pr litre. Very strange indeed! And very annoying here in Australia as there are so vast distances here and long range would have been gokd worth.

There is another thread about fuel consumption where a Ten owner says he had issues with the sparkplug and that with a irridium spark plug his Ten is back to that bikes normal 4,2 litres pr 100 kms - which is approx 24 kms pr litre. So there certainly are others that gets as many kms out of each litre of fuel as I (used) to do.
By the way - maybe I should check if there is a irridium spark plug on the bike???

Thanks for your safe travels wish by the way. Heading over the Nullabors later this week.....

Where are you now, are you in Perth?? Can't say I have a solution but if you want to do any work, service, adjust etc before you head east let me know as you are welcome to my workshop and tools.
Matt.

Yeas I am in Perth right now. And thanks so much for the offer - much appriciated. However I am well housed and fed here in Perth so no worries about that.

I would have liked to adjust down the fuel consumption a bit though.....:eusa_think: