There is a black new left hand tank panel on bay �16.99 bargain.

http://cgi.ebay.co.uk/YAMAHA-XT660-X...#ht_1829wt_689

thanks tony, just ordered. hopefully it will be the correct one to fit my steed

It's the correct one for your bike. Fear not my friend.

Hi there,

I made myself a Kev fuel mod and played with my Co setting. This was all I really needed. Then when the air filter needed replacing got a DNA and stage 2, These definately helped my bike pull better, and made a nice change to the sound.

I recently got a PCV and it helped with more power, but even with a custom map, couldn't get it as smooth throttle response as with the Kev Mod. ECU to blame.
So the options there are to get an 02 eliminator (I believe is still in development) or replace ecu and wire loom.
But I'm in no hurry, Air filters and Kev fuel mod, for me, job done (for now anyway tee hee)
I've increased rear sprocket by 1 tooth (shop sent me the wrong one - but I like it), bike pulls away even faster and pulls better at lower revs, but if you are coming from a higher revving bike, this is probably the wrong thing for you to do. (You'll run out of revs even quicker).
This single cylinder bike just needs getting to know abit.
:)

Pm Kev about his new o2 mod it works and sorts out the surging