I have beaten this with a dead horse already and am getting very frustrated. I have tried just about every conceivable jetting combination and nothing has worked. The bike still sputters and then takes off then sputters and takes off only in 5th gear. I can gradually give it gas through out the sputtering to eventually get it up to speed. The sputtering starts from as little as 1/8 throttle all the way up. What else besides jetting could be causing this? Again, this ONLY affects 5th gear. The bike runs very smooth up to 4th gear with plenty of power and no sputtering. I figured if it was the clutch it would affect all gears. I can lug this up a hill in 3rd and still not slip. I tried every which way to get it to happen in other gears this last weekend. I even put a new spark plug in before I rode. Any suggestions please! I am running out of patience.