Hi Tony
I've had a blue xt660x for 2 years now and had a fair bit of help and advice from Kev. I too couldn't believe how poor the fueling was/is even up to this week I was still messing about with it.
I,ve put kev,s mod on, changed the filter system,fitted o2 sensor eliminator, modified the throttle but the fueling is still not perfect, better but not right.
But here's the rub!
over the last year or so I have been lucky enough to have use of some pretty decent bikes, harley electra glide, victory 8ball, triumph Rocket 3,Triumph Thunderbird and you know what, I jump back on the Yam its a laugh a minute on virtually every occasion.
I,ve used it for a weeks camping i use it every day for work i,ve taken it out for runs with mates on all sorts of sports bikes and cruisers its never at the back and it never feels like its straining.
i think this is the worst time of year for the 660 as your in the wet on part throttle and its horrible at times. if you wait till the roads dry up and you can give it some stick I think you'll see a different bike.
sorry to ramble but just a thought, have you tried altering the CO level?

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