[Cpeterson]

I have a 06 yfz450 it won’t idle right keeps shutting off of small back fire and dies without any throttle I have recently rebuilt the carb switch to a pro design adapter and k&n filter I have a 52 pilot and 168 main 3 clip on needle I live in north est part of Ohio so like 500 ft sea level. I have to have my fuel screw out more then 3 turns to get it to idle as fare as I know motor is stock bore

 

[dust n' u]

try going down on the pilot and fuel screw to 2 turns out.

 

[Cpeterson]

try going down on the pilot and fuel screw to 2 turns out.

I have I tried a 48 45 and a 50 and fuel screw at fuel screw had to be way out on all the jets

 

[Yfsheee]

Did something get put back together wrong in the carb? How does the air boot look?

 

[Cpeterson]

Did something get put back together wrong in the carb? How does the air boot look?

Boot looks ok and I think the problem was in multiple areas the mid body on the carb had bad gaskets I found that 3 valves were out of spec and the timing chain was stretch. I have pulled everything apart new top end gaskets shimmed the valve and waiting on carb kit and I’ll update if problems are solved

 

[Yfsheee]

Good deal!! My quad was severely out of spec on valve shims for a long time and when I finally changed the sims the valves were slightly held open.

 

[Yfsheee]

I would also make sure the airboot clamps are tight enough when you put it back together, mine had that prob and that's what it turned out to be