50cc to 80cc By wldr4life77 (Read 340 times)

[wldr4life77]

I installed a big bore kit on my 50cc gy6. Starts right up and runs well. Still has stock carb. Backfires/pops really bad on rapid deceleration. I read it was a lean condition so I tried backing out air/fuel screw…counterclockwise. Saw no changes at all. Still backfiring/popping. Need help please to get it to stop. Neve did that before.

[dyoung1167]

to begin you can change how high the main needle in the carbe to ride higher making run a bit richer but probably not help with your prob as it is more likely the idle jet causing the lean after throttle drop. kits with numerous size of both low speed and high speed jets are fairly cheap and easy to mess with. there are probably threads on here to better explain and many ytube vids out there.

[kz1000st]

It could be an air leak somewhere in the exhaust. Is the pair valve line tight? It's the doohickey sitting on the valve cover.