Hi All,

My 2008 XT660R has been laid up for a year as it wouldn't start and I kinda lost interest in the poor thing for a bit. This week I have the bug again and sorted out the non starting issue (corroded terminals for RH switch gear under the tank).

I took it round the block and it seems the speedo over reads massively (3rd gear approx 30mph it thinks I am doing 108!), on tickover in 1st on the stand it reads 21mph. I have checked the pulses from the speed sensor and it appears to go between 0.4 and 4.8V about 6-8 times for 1 turn of the rear wheel, I suspect the speed sensor is faulty and I wondered if anyone else has any views on this?

Up until 2013 when it went wrong I had done 32000 miles in all weathers and have pulled apart every connector and cleaned the terminals as some were quite corroded. The speedo was working ok up to the point the bike went wrong.

Looks like speedometer eeprom problem. http://www.xt660.com/showthread.php?...=kullam&page=2

Thanks for the reply, I think it is the same as my Diag mode 7 counts up to 999 before returning to 0. Could you tell me how you fixed yours? I have searched and there are no instructions on how you reprogram the eeprom.

First you have to take your speedo apart, it's the hardest part because it's glued. I grinded indicator lights bottom edge little bit and after that used knife to open it carefully. If you get your speedo apart then you have to desolder display and under there is eeprom, you have to desolder it. Then you need new eeprom S24CS0 and here is eeprom dump files http://www.xt-660.de/forum/viewtopic.php?f=3&t=9590 . You also need eeprom programming tool, arduino or something. Then you need PonyProg and you have to write numbers from german forum Tausch Tacho to PonyProg, very long proces, and if you want your odo right then you need to rewrite all odo reading addresses and calculate new cheksums and new master cheksum to. After that write it to eeprom and solder eeprom and display back and test it. My friend offers repair service in ebay but i don't know is this offer active, i can ask what was price. Also found this http://www.ebay.com/itm/NEW-GENUINE-...42da20&vxp=mtr

Thanks for all your help Kullam, it is appreciated. I think I have the missing pieces now, will try to reprogram and if not I will buy a new speedo.

Paul

My friend made ebay offering active again. Here's the link: http://www.ebay.com/itm/Yamaha-XT660...339068&vxp=mtr
After repair, i can test speedos and chek everything is ok.

Hello,

I see that this item is some years old, but currently I have the same issue on my XT660R Yamaha from 2007, and it looks like I have to re-write the eeprom as you describe there.
Unfortunately it looks like the EEPROM dump files which you mentioned there are no longer available at the link. Is there any chance to help me with that?

Or is there any chance to send it to someone for this repair?

Thank you in advance,