Gy6 50cc backfiring and bogging

[padly1995]

Hello,
i started with scooter i bought for cheap because it was working realy bad and it died in one week.
I putted in:
ONE YEAR OLD:
-clutch
-carburetor
-cdi
-coil
-spark plug cap
-spark cable

AND NEW:
-piston and cilynder
-stator and magneto
-oil

I also ajdusted the valves 100% perfectly, and i had to put the carb needle washer to the toppest position, after changing the piston and cilynder, otherwise it was bogging and backfiring like crazy at more than 1/4 throttle (thats realy strange because with old piston and cilynder it was working fine with washer on lowest position)!

Here is the problem: i cleaned the carb and it ran great for 3 days, than it started backfiring and losing power at acceleration, than i cleaned the carb again and it was good again for 3 days; 1 month it was like that.

I noticed that turning A/F screw does not giving any effect at all, i also removed auto choke needle, because it wasnt working at all.

Yesterday i took a little bit of silincer out and it was running alot beter, but than it started backfiring again; I cleaned the carb and nothing, than i changed the spark plug, it was a little better, but not much. Than i removed the plugin from line that goes from the airbox to carb and it was good again, but after 5 miles it started backfiring again. I cleaned the carb and air filter and it wasnt any better.

Thank you for anwsers, my english is not perfect, so i hope you understood it cheers!