Common Problems
XTX & XTR
Cutting out/ Stalling.
This is my research having tested every XT660 ECU from 2004 to 2010 models.
The main problem is Yamaha built a over run fuel shut off system in the fuel injection mapping on the 00 & 01 ECU's 2004 to 2006, so when the throttle is closed & the revs are dropping the ECU shuts off the fuel injecting with the A/F ratio higher than 18:1 until 1750rpm for the 00 ECU & 2000rpm for the 01 ECU then it starts injecting again so the bike can get ready for the idle speed, with the fuel been shut off then start to inject again the motor sometimes battles to keep running & cuts out.
Adding more fuel in the zero zone from 1750 to 2250rpm range using a Power Commander does not fix the cutting out on the 00 & 01 ECU's, adjusting the TPS to 16 & setting the idle to 1500 rpm works better.
With 10 & 11 ECU's 2007 to 2010 models the over run cut off was no longer used & these ECU's only lean the A/F ratio out to 14:1 when the throttle is closed all the way to idle, this almost fixed the cutting out on the 10 & 11 ECU's. The solution for the 10 & 11 ECU s to add fuel in the zero to 2% zones from 1750rpm to 2250 rpm by 5%, this stops the 10 & 11 ECU's from stalling & set your idle speed to 1500 rpm.
Also make sure you TPS is not in the faulty range.
Make sure idle speed is set correct. I would recommending 1500RPM for all years.
http://www.xt660.com/showpost.php?p=22834&postcount=10
Set you CO1 up by at least 10 from your standard dash reading.
http://www.xt660.com/showpost.php?p=174&postcount=1
Make sure your TPS is reading correctly.
http://www.xt660.com/showpost.php?p=175&postcount=1
Recall, there was a recall for TPS on 2004 to 2005 models. Just make sure they fit the new A2 type not the same faulty A1 type.
http://xt660.com/showpost.php?p=15728&postcount=1
http://xt660.com/showthread.php?t=948
Surging
We have all had our share of surging when we first got our bikes. This can be greatly reduced.
Make sure your drive chain is adjusted correctly, not to loose.
Check your sprocket drive rubbers that you do not have any play in them. There should not be any free play when you move the rear sprocket back & forwards. Look in the mod section if you have ree play on the sprocket holder.
Adjust up your CO1.
http://www.xt660.com/showpost.php?p=174&postcount=1
2004 to 2005 models have old software with bad fuelling with a Engine ECU part number that ends with a 00, some riders have had luck in getting Yamaha to replace their Engine ECU's with a 01 ECU. This improves the slow riding conditions greatly & is well worth trying to get your hands on a 01 ECU. If you have a 00 ECU remove the ECU & check for a white paint dot on the back of it, if it has this white dot it means you have e remapped ECU & does not require an updated 01 ECU.
Have a look in the mod section for information on all ECU's
Make sure your TPS is set correctly
http://www.xt660.com/showpost.php?p=175&postcount=1
Below links will give you some ideas as to mods that can be done to smooth out your XT...
(1) Join XT660.com supporters to access the “Ask Kev” 1:1 technical help section -
http://www.xt660.com/payments.php
(2) Check you haven’t got a dodgy TPS (which you’ve already done and got fixed) -
http://www.xt660.com/showthread.php?t=948
Yamaha Recall
(3) Check you haven’t got a dodgy ECU -
http://www.xt660.com/showthread.php?t=519
Yamaha Recall
http://www.xt660.com/showthread.php?t=8546 (How to recognise the different ECUs)
(4) Twist-grip mod -
http://www.xt660.com/showthread.php?p=154983
(5) Cush drive rubber mod -
http://www.xt660.com/showthread.php?t=12422
(6) Adjust your CO -
http://www.xt660.com/showthread.php?t=55
(7) Adjust your TPS -
http://www.xt660.com/showthread.php?t=56
(8) Fit Kev’s fuel mod -
http://www.xt660.com/showthread.php?t=194
(9) Kev's o2 controller
http://www.ebay.com.au/sch/7416kevxt...p2047675.l2562
Fitting a fuelling device almost fixes most of the surging, there are a few options.
The best result for no surging is, up your CO1 by 15 to 20 & a Power commander with a custom made fuel map, TPS set to 16.
For the 07/09 models surging, as above & up your CO1 by 10, make sure your idle is set to 1500RPM. I now have a fix for 2007 to present XT660X & XT660R's with O2 sensor.
8/Kev's 2010 New O2 Mod for XTX & XTR's
http://www.xt660.com/showthread.php?t=14746