Fuerza wont idle and i cant figure it out!

[Kbassi78]

ive had my fuerza for about 5 months and it has been great. ive done a bunch of upgrades and everything has worked out well until now. while riding a couple days ago, the bike started, idled, rode perfectly fine for about a half hour until i tried to accelerate away from a stop light and the bike would sputter and backfire as soon as i twisted the throttle. still idled just fine but would not accelerate - i couldnt get above 15mph. i bought a mikuni knock off and assumed that was the problem. coincidentally my real mikuni arrived a day later so i put that on assuming it would fix the problem. now i cant even get the bike to idle. it will only start if i give it 1/4-1/2 throttle and even then it will run like absolute garbage and not rev up, then die as soon as i release the throttle. i have checked everything i can think of - cleaned the carb, checked the fuel line, replaced the spark plug, changed the jets to and from stock, adjusted mixture and idle screw in every combination i can think of. if i try starting it with the choke it will not start at all. so ive done some research and the next step will be checking the timing and valve clearance. has anyone else had this problem? any idea what it could be?

[RedCrowRides]

Given it's been 5 months and the symptoms you mention, the FIRST thing i would do is adjust the valve clearances.these bikes work so hard that proper valve lash just dont last ,they do need adjusting fairly frequently .Valves being too tight will result in conditions that seem like carb / jetting issues but really arent, and if the valve lash is bad no matter what you do to the carb it wont run right.


So, set the valves and see where you are after that, also check all your rubber boots if there are any and make sure they are all in good shape, it doesnt take much of a gouge ,rip, or tear to make a vacuum leak that will make proper tuning impossible , but i'm guessing you're issue is almost certainly the valves have tightened up over time .