high fuel consumption and some weird stuff
 

Hi Folks,

For a couple of months now i own a xt660z tennere currently 45000 km on the clock.
From the beginning i had a really high fuel consumption with an avg km/L of 15.

I changed the spark plug, air filter cleaned all the electrical connections and checked all the electrical components, adjusted the valves. Everything was in spec.
And still the high fuel consumption.

Then i noticed a strange wire coming from the fuel injector ground to the white ground connector at the battery.
It seams like there is a kind of fuse in the middle of the wire so i cut it open, but to my surprise there was no fuse but a 3w light bulb to have some king if resistance i think. I could imagine this was made to richen the bikes fuel to air mix.

So i removed the wire and light bulb had to readjust the idle speed because it was now way to high above 2000 rpm.
And it seems that the bike now runs much smoother, filled her up with a full tank of fresh gas and reset the trip.
Fingers cross if this will fix my fuel consumption problem.

very Strange....Prob got the idea from the net....
some weid ideas out there...

I get 23/24km/liter from my XTR...
15 is drinking the stuff....



..

Yep. At traffic lichts you can really smell the fuel and on hard acceleration it gives two big plumes of smoke.

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I have issues with high fuel consumption myself. When bike was new I got 27-28 kms pr liter. Then I put both Kev mods, KNA airfilter and changed gearing from 15/45 to 15/48 and got 24-25 kms pr liter with that set up. After a long overland tour and after a full service I know got only around 20 kms pr liter.

Im a relative lean rider, seldom pass 100 km/h and on highways most often ride around 90-95 km/h. Have checked all that I can come up to check. And bike has had another full service but still the same fuel consumption. Other EFI 650 bikes easily gets +25 kms pr liter so Im very disappointed with the Tenere...

It seems that is had fixed my problem.
Got 25Km/L out of it.

Have you checked the Injector itself? Running a bit of injector cleaner might help? The bike shop I use here tell me that WR's sometimes give injector problems & although the bike is 12volt the injector actually runs around 6volt so connecting it directly to a battery effectively gives it a heart attack so to speak thus clearing it out as well. I couldn't be sure if the XT is the same, just food for thought as it's been an ongoing issue for you.

You might be right, you might just be right. Have heard it from others as well. As I have been riding through eastern-Europe, central Asia, southeast Asia etc I have had all kinds of different fuel on the tank, so ut makes sense that the injector can be a bit clogged.

So where do I start? Do I start with adding some injector cleaner on the tank? Has anyone any experience with that?
Shall I ask to get the injector cleaned at next full service? Can a normal/average Yamaha garage do this - injector cleaning?

Any advices appriciated...

Sorry for intermingling here but my tenere (2010) is high fuel consuming too. Fairly new bike, was 10k on it and now almost 17k. It does 16 km on a liter. Almost 4 cilinder usage. I bought it with a PCV, scorpion exhaust and stage 2 air filter. I got the stage 3 now and still the same. Is it probably due to the pcv settings? Because I was going for a dyno but its a bit pricey so I was searching for another solution. Hope someone could help us out. Think we all bought the tenere for the low consumption :(

PS: If anybody has some pcv maps for me I'd appreciate.

On the other hand - I have had the exhaust checked and the result was very near to perfect. The garage who did it said it was as just a tiny tiny tad rich - nothing at all that can explain 20 % increase in fuel consume.
I guess since the exhaust is ok all things with engine, injection, valves, spark plug, air filter etc can be rules out. Have to start looking for something that make resistance to the bike while rolling. Its not brakes hanging, both wheels seem to spin fine. But the rear wheel bearings were changed just before the increase in fuel started...is there any chance it can be those?

My is the same. About 16-18 km/L ...

First check all the simple stuff.
Make sure the valve clearance is right and the air filter is clean.
Spray some brake cleaner around the throttle body to see if there are any vacuum leaks. The engine rpm fluctuate if there is.

Check the spark plug this will give a good indication on how the engine is running black is to rich.

Also check the electrical components resistance. Injector, tps etc... the correct values are in the workshop manual and Haynes manual.

In my case I had a ground problem on the injector cable under the tank.
Remove the tank and check the cable for wear and tear maybe it is making contact on the frame.

If this is the case the injector will always give a full blast of fuel resulting in bad running, black smoke, fuel smell from Exhaust and off course bad mileage.

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Thanks for input. I have checked all you mention except the injector and electrical components - which ones do you mean by the way? I have had a garage to check via the diagnose system - but nothing was found.

And as I mentioned in my last post - I have also had the exhaust checked and it was very very near perfect. So that should mean that I can rule out injector, censors and engine as a whole - I presume, and start to look for something else....

Its so damned irritating that I earlier on easily could get 25 kms pr liter - 70 mpg without thinking about saving fuel and nowadays I can get only
20-22 kms pr liter - 55-60 mpg - constantly riding in fuel saving modus at max 90-95 km/h.....

Hi there,

I have a similar trouble now... almost +20% fuel consumption if i compare to when i bough the bike.
So i fitted kev O2 and fuel mods, as well as dna air filter... but that was way before the consumption went higher. Tryed with the fuel mod set to 0, no change.
Filter is clean. Spark plug looks ok, i'd say the bike runs fine except for the consumption.
I also added an aftermarket exhaust (i can't see that increasing fuel consumption that way, plus it has no cats now...)

What may play a role is that i fitted a slightly bigger and less street oriented rear tire. I can see that decrease my mpg as i look at the odo to calculate it+ dirt tire will waste more energy on the slab. But not THAT much

Any idea what to look for, before i give a shot at putting everything back to stock (remove kev mod, stock filter and snorkle, stock exhaust) ?

I have always used a fuel system cleaner in the petrol every so often, like STP or Redex or similar. I think that this helps to keep the injector system clean. Simply add to the fuel tank when you fill up.

And ps I used to get 20 km per litre from my XT660X, riding it as fast as possible. 15 is terrible.....

Thanks for your reply. Yes 20km/L was the worst i was getting at first. Now i'm always under that.
I'd say consumption has been increasing slowly... so i will make a try or two with curative fuel cleaner.

What fuel are you using? 95RON? 97/98RON? E5 or E10? The latest E10 fuels (10% ethanol) will contribute to higher fuel consumption as ethanol has a lower energy content than petrol. The more ethanol the higher the fuel consumption will be for any given engine/road speed.

As they are sneaking up the ethanol content in forecourt petrol every year it is quite plausible that you are finding your bike's mpg gradually getting worse. Nine years ago here in the UK (when I bought my XTZ) the vast majority of petrol was E0 (no ethanol). By the end of 2018, when my bike is ten years old, it will almost all be E10, a completely different fuel from that the XT was originally designed to run on.

I'm aware of that. In France we get 98/95/95 E10. I try to get them in that order of priority. I think SP98 and SP95 have 5% ethanol though, but that's not new.