Recently I have been riding my bike and noticing that it seems to cut out at full throttle way before the rev limiter. When I first bought the bike it ran great and lately I have been getting annoyed at the problem. I have tried different main jets(larger and smaller) new air filter , spark plug, but I still get the same result...Poor response at WOT. So today I am out riding again after changing the jet again and still having the same problem. I am sitting on top of a mountain pulling my hair out when I look down at my little clear fuel filter which is empty. I think hmmm... "why is that empty"...so I check the petcok and it is in the proper position (not reserver and not off). So I tap the filter and it slowly fills up. Then I start up the bike and look down at it and rev it up a bit it uses all the fuel. It runs well at a low idle but crack the throttle wide open and it sputters and spits like its not getting enough fuel and the fuel filter is devoid of fuel until I let off the throttle and then it fills up. I am thinking to myself "could it be the Petcok?". So I change the position of the petcok to reserve and the filter fills up immediately and BAM I no longer have the sputtering spitting lean condition I had before and I once again had a smile on my face. . So has anyone experienced a fuel petcok problem on their bike similar to this?