xt660x fuel consuption problem
 

hi everyone
im writing because i have a problem with my love.. and the story is

8/28/13bought with 18,000 + km

After about a month ι get it to a general service (oil filter blends check spark plug etc) and a full check to know if is there something needs something

before service the fuel light turned on at about 170-180 km
after the service the light turned on at about 130 km
the mechanic aftem my complaining about increased consuption trimed the fuel mixure a lot of times but nothing better .. the fuel consuption was about 7.5 litres per 100km
after going to a lot of mechanics that noone could find and fix the problem the consuption suddenly was normal again (fuel light at 170-180 km ) that means 5-6 l/100km
after 20k klms the problem come again ..
i checked the valves ...ok
cleaned the air filter ....
cleaned the fuel injector ..
but the problem remain ..
i dont know what to do after all these ...
mixture is at no 5
tps position at 17
and all the other settings are ok ...
what to do ???????

The difference between 7.5L/100Km and 5L/100Km is A LOT - 50% worse!!

I see you've checked a number of engine/intake components, but have you checked other more simple things like whether the brakes are binding or if there's and actual fuel leak somewhere?

Not sure how the mechanic managed to "trim" the fuelling unless you've got a Power commander fitted?

Are you working out the economy with the trip meter and measuring the fuel you actually put in, or are you just going on when the low fuel light turns on? The fuel level lights/gauges on XTs are not known for there accuracy or consistency! ;)

hi bro .. i've checked all the components that have to do with fuel .. no leaks ..nothing
i check the consumption by 2 ways... when the light turns on ..and by the fuel and klms ive done ... maybe ecu problem ??? i dont know ...

check for sticking brakes as previously suggested.
I assume the mechanic checked the CO setting which may have a small effect on fuel consumption.
You really need to check the consumption with fuel you put in to fill up and the odometer and not the light.
Nevertheless, for comparison, my light comes on between 130~ 160 MILES (depending on where and how I ride).
In addition to what you have checked and what has been suggested, I would do the following:
- change the spark plug
- what engine oil are you using (a good synth will give you and extra 10% range)
- tyres affect consumption. chunky ones are worse
- check your tyres are not under inflated
- fuel quality and ethanol can reduce your range
- change in riding: more traffic and city ride = reduced range
- change lube and slack adjustment

I don't know the climate and temperatures where you live but winter riding (0~10deg) will reduce your range by about 10%

An iridium spark plug can reduce the fuel consumption. Maybe the guy who owned the bike before plugged one in and they changed it at the service to a standard spark plug again.

I experienced it at my Z. My bike used about a liter more with an almost new standard spark plug. After like 2000 km with the standard Spark plug i experience a tremendous increase of fuel consumption. After changing back to my used iridium spark plug that had already 8000km done the problem was gone. After 16000 km the iridium spark plug still works like a charm with 4,2 liters per 100km. But now it is time to change it to a new one ;).

Maybe u can also check if the ignition coil works correct. Maybe there is some partial short cut that occurs when the engine vibrates so there will misfiring ignition sparks. Or the plug of the spark plug is broken.

your comment abt iridium plug is interesting.

I decided to change my original plug @ 8.5k miles (instead of 12k interval) because of the engine vibration had become too noticeable.

the change got the engine to purr again. Didn't go for iridium as I wasn't sure if the plug change would cure the vibes.

At the next change I will try the iridium if the fuel consumption improves

I can imagine the effect with the fuel consumption will be more if the bike has a really lean set up. My bike has an OTR Exhaust with the OTR foam filter and the snorkel is removed too. So there is going a lot of air through the engine. The fuel/air ratio is really bad. I have to ride it above 2500 rpm otherwise it surges too much. This modifications must have extended the fuel consumption effect of the iridium spark plug compared to the standard spark plug.

But anyway it is one of the cheapest thing that will improve your fuel consumption and the surging. When u just calculate that u save 0.1 Liters on 100 km with a price of 1.5 dollar per liter of fuel. U will save 15 dollars on 10000km which means your iridium spark plug is for free.

I will certainly consider the iridium plug on my original / standard XTR.

It sounds like the OTR exhaust does not have fitting for the O2 sensor in which case you fuelling will not be optimum unless you do some of the mods you find in the forum

Or modify the exhaust so that you can mount the O2 sensor