This is a brand new Kitaco 50cc Power Pack specially manufactured by Kitaco co. in Osaka Japan.
It is designed for Honda Z50J Monkey 12V and other minibikes
Please refer to your own specific vehicle and engine for compatibility
Brand new in box.
Here are several technical informations from manufacturer:

DESCRIPTION
A SET OF HIGH COMPRESSION PISTON, HIGH CAMSHAFT & KEIHIN PC φ20 LIGHT CARBURETOR KIT WITH 50cc
MUFFLER EXCHANGE, ELECTRIC TUNING & PORT MODS RECOMMENDED.

REMARKS
※1 FUEL COCK TYPE 1 IS REQUIRED FOR DAX50.
※2 THROTTLE HOLDER MODS AND THROTTLE CABLE (SOLD SEPARATELY) REQUIRED
○BORE:φ39
○PISTON:FORGED 2R/WPC+MOS2 MODS
○WEIGHT:35g(STOCK40g)
○CARBURETOR
○M/J#85 P/J#35 ASSEMBLED
※STOCK AIR CLEANER NOT USEABLE


APPLICATION
MONKEY/GORILLA
FNO,Z50J-2000001~
FNO,AB27-1000001~1899999
MONKEY BAJA
ALL MODELS
DAX50※1
AB26 ALL MODELS
JAZZ
ALL MODELS
XR50R/CRF50F※2
AE03 ALL MODELS