Running lean concerns
 

Hi, I have a 2008 Tenere and recently replaced the exhaust with a single aftermarket can, my standard air filter was replaced by Yamaha with a DNA stage two filter with the DNA stage one insert. I am concerned that my engine might be running to lean. I have installed my own DIY KEVMOD (thanks kev), but instead I have measured the resistance to drop the temp by more or less 5 � 6 degrees and soldered a 470 ohm resistor inline with the airtemp sensor. I have also removed the stage one insert from the DNA filter and now running stage two. Although the bike is running fine I am still concerned that I might be causing engine damage by running to lean? I will post some pics of my sparkplug colour later.

Firstly welcome to the foum mate.

470 ohms resistance is not enough resistance for a XTZ fuel mod with your mods, you need 3000 to 5000 ohms on a Z with those mods to get the A/F ratio in a safe zone. Also do the AIS mod to stop the popping back in the exhaust.

My current fuel mod for a XTZ runs a 10K ohm variable resistor. The main forums main web page can't be update at the moment, I will update it in the near future when the problem has been sorted.

Running lean question
 

Thanks for the info kev, think I will put back the DNA restrictor to be save, I have measured the airtemp sensor at around 27 degrees C�s and the resistance was about 1.8k ohm, when I increased the temp to 36 degrees C�s it did go down to about 1.2 or 1.3k ohm�s. Will I be able to determine if the fuel/air ratio is in the right range by looking at the sparkplug? I have done the AIS mod and it did helped a lot with the backfiring - thanks again for all the info.

I measured the A/F ratio using a Wide Band Power Commander so no quess work was done, connect a 5K resistor in series & you will be safe.

Checking the plug with unleaded fuels these days is a bit of guess work.

Running lean concerns
 

Thanks will do that.

High fuel consumption
 

I have connected a 4k7 resistor in series with the airtemp sensor. Running great, but my fuel consumption went down from about 20km/litre to 15km/litre. Any suggestions?

Try to use less throttle... sorry temptation was too great.. I'll get me coat.


the fuel mod is a broad brush. If you want optimum fuel economy and power then a fuel mapping device will be need to get it right ..ie PCV, PCIII etc... and then a proper map to address what you want. ps finding someone who can do a good map is probably the hardest part (apart from spending the wonga in the 1st place)

+1.

At least you can see the resistor trick works, use a less resistance resistor 3K.

Ok, http://www.xt660.com/images/icons/icon14.gif connected a 5k pot and turned it down to 2.5k, will let you know what the outcome is.