G- Cylinder Head 47mm 72cc 2V 18.4/16 Fit 69mm (139QMB)
Description: Cylinder Head 47mm 72cc 2V 18.4/16 Fit 69mm for 139QMB 49/50cc 4-stroke engines. Common problems with stock cylinder heads on the Chinese 4-stroke engines are generally known to be expensive repair maintenance costs. Chinese replacement cylinder heads for GY6 engines are only of medium build quality at best.
When used in conjunction with a stock stroke of 41.4mm the engine displacement comes out to 72cc! When used with a 44mm stroker crank, engine displacement = 76.3cc!
NOTE: Most stock 139QMB cylinder head's valve height is 69mm which comes standard with its 69mm rocker arm. This Cylinder Head's valve height is 69mm and will work only with a 69mm rocker arm only. If you need a set of 69mm rocker arm see Part# 151-247 sold separately.
Includes the following Cylinder head, and Valve assembly.
• 1x Cylinder Head Stud Space: 50mm / H: 60mm / Intake Port: 17mm / Exhaust Port: 18mm
• 2x Valves: 18.4x69mm Intake / 16x64mm Exhaust / Stem: 5mm
• Overall Height (w/valves) H: 71.1<72.3mm
• Cylinder Height (w/o valves): 59.5mm
• 6mm Intake Threads
• 6mm Exhaust Threads
• Fit Intake Studs: M6 / Nuts: M6 / Socket: 10mm
• Fit Exhaust Studs: M6 / Nuts: M6 / Socket: 10mm
• Fit Rocker Arm Assembly: 69mm / Feeler Gauge: .004in / .005in / Socket: 9mm
• Fit Cylinder Studs: 168mm 176mm / Nuts: M7 / Washers: M7 / Side Bolts: M6 / Socket: 8mm-10mm
• Fit 50mm Stud Spacing /Diagonal 70.5mm
• Fit Crankshaft 41.4mm to 44mm
• Fit Dowel Pin Set (8x14mm)
• Fit QMB 49/50cc+
Supported Models: 139QMB 49cc-50cc engines, Baja SC50, Boreem (BMS) 50, Filly 50, Kymco 50, Panterra 50, Qingqi 50, QLink 50, Roketa 50, SUNL 50, SYM 50, Tank 50, TaoTao 50, and virtually any other scooter engine with these measurements.
Item Weight & Product Dimensions:
• 2.243 Pounds | 5.327" (L) x 5.323" (W) x 2.598" (H)