New old bike today :)

[Mikekitts81]

Bought a new to me but old 2004 xt660x today and i most say its another big cyclinder to my stable aswell as the 660 baghira and the 640 lc4 ktm iam working on ... the bike as just over 20,000 miles on it with full service history etc and as had all services and history with money not being a expense ... now the only thing thats bugging me is at low end the bike is a bit funny like its surging and the throttle response is a bit edgey ... at full throttle great mid range belting just seems to be abit jumpy amd jittery at low revs ....

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Know i no there a few on here with the yamaha xt660 wether its a x r or z so whats the best way to sort it as iam assuming its common with lots of them as theres stuff online about them but cant find a definitif answer on a fix theres a kev mod then people saying about filter changes to s1 s2s air box mods etc ... and iam wondering wether its sommat iam going to have to live with ... its riding is great its just low revs it seems abit jittery ...

[herman]

https://www.xt660.com/index.php is your best bet. I certainly made mine better but I cant for the life of me remember the specifics, too many bikes ago. I seem to remember altering codes on the dash coupled with an air box mod. Nice bike

[chunky butt]

https://www.xt660.com/index.php is your best bet. I certainly made mine better but I cant for the life of me remember the specifics, too many bikes ago. I seem to remember altering codes on the dash coupled with an air box mod. Nice bike

Yep, as Allan says, all your answers on xt660.com, got a z me self, great all round bike

[Neil M]

I think you need the 'Kev mod'. Seem to remember BondYZF on here had a very sorted 660.

Good bikes when tweaked.

[minkyhead]

i think ive got a kev mod sensor somwhere .off me old tenere ? ..ill have a dig around in the chaos boxes
14 tooth front is pretty standard on all xts off road ....
daves had his for years and its a good bus ..i know he put a softer cam on the throttle and was pleased with that ..hes done some miles on that xt ..

Grabbed Frame 117 by minkyhead56, on Flickrhttps://www.youtube.com/watch?v=eDgVtkAZujY

[Mikekitts81]

ill have it off you and see if it helps minky if you have one. just message me and ill sort out picking it up or posting etc and a price . as for 14 tooth front sprocket i was gonna leave it same as it is it could already be one not looked yet . just bought the bike as a winter hack really to ride over winter while the others are being worked on . the bike i feel was relativily cheap at 1700 and the service history etc is better than most that are at 2500 upwards. its fully stamped in the service book loads of work recepits all shop services and work done so i assume the guy didnt do anything hiself .not even the oil changes etc were done by him everything seems to be done by the shop. its just this twithcy jerky low rev problem that is a pain . i read somewhere that yamaha always seem to run the bikes lean from new as it helps keep the breakages down meaning less come backs within the first few years of owner ship wether its true or not i dont no did think of running the co2 setting a little higher making it run a bit richer . cant really find a answer on what the kev mods acutally does but alot seem to swear by it thou .

[minkyhead]

as i remember it sends false readings as to air temperature fooling it to thinking its colder which in turn instrructs it to squirt more feul at lower revs probably the tickover closed loop part of the system ....ill have a look ..hopfully i can track it down

[Mikekitts81]

Had a look internal today minky and the kev mod is already on it iam thinking its something else now.

[Helicoptermanr22]

Mine is the same as they all are. Mines done 2300 miles and worth the expenditure. Ive just ordered a kev o2 mod for £80 which will i hope smooth out tue bottom end without altering mid or top revs.
They run too lean at the bottom hence surging. Its a fixable issue and there are much more you can do them.