GY6 & CN250 CVK Main Jet Tuning Kit 10PCS GY6 and CN250 CVK Main Jet Kit for 150cc and 125cc GY6 carburetors and 250cc 4-stroke water-cooled 172mm carburetors, includes a size range from #100 - #140. Available in 10 piece or 50 piece set. Keihin Round Style Main Jet Kit Available in 10 Piece or 50 Piece Sets Includes The Following Sizes: 100, 105, 108, 110, 114, 115, 120, 125, 130 & 140 10 Piece Set Has 1 of Each Size, 50 Piece Set Has 5 of Each Size Thread Size: M5x0.80 Overall Length: 8mm Please Select Number of Pieces from Drop-Down Menu