Blue Line 4T Big Bore w/ Head (72cc, 69mm Valves): 139QMB

Complete 72cc, 69mm iron cylinder and head kit for 50cc 4-stroke 139QMB engines with 69mm valves. Pump up that weak engine to a respectable 72cc displacement, on a budget. It won't turn your scoot a screaming race-machine, but will give you the nice bump in power that you need. 

NOTE: Before ordering, remove the valve from your scooter's head and measure the full length of the valve stem. This kit works with 69mm valves. If your scooter has 64mm valves, you'll need the following 64mm big bore kit.

Specifications:

• Cast aluminum piston: 47mm (not shown)
• 5 piston rings: 47mm
• Wrist pin w/G-clips: 41mm x 13mm x 8mm
• Cast iron cylinder: 47mm
• Outer sleeve diameter: 49.5mm
• Overall height (w/sleeve): 70.3mm
• Cylinder height (w/o sleeve): 53mm
• Includes cylinder head 47mm 2V NON-EGR, valve assembly
• Cylinder head stud spacing: 50mm, H: 60mm
• Intake Port: 17mm
• Exhaust port: 18mm
• 2 valves: 18.4x69mm Intake, 16x69mm Exhaust
• Stem: 5mm
• Overall height (w/valves) H: 71.1<72.3mm
• Cylinder height (w/o valves): 59.5mm
• Includes two 6mm intake studs, two 6mm exhaust studs
  

Compatibility:

139QMB-based 50cc / 80cc engines with the following engine codes:

Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.

About Blue Line: Blue Line offers OEM equivalent replacement parts for on-road scooters. Blue Line parts are a direct-fit replacement when OEM parts are unavailable or overly expensive for your scooter. Since 2018, Blue Line has provided quality parts at great prices.

Brands: Amstar, Amigo, Ascend, Baotian, Bashan, Blade, Boom, Chicago Scooter Company, Dongfang, Roketa, Baotian, Bashan, BMS, Cool Sports, E Ton, Fly Wing, Eagle, Fly, Italica, Riya, Ice Bear, Jackel, Jet Moto, JCL, Taotao, Peace, JM Star, Jonway, Kazuma, Keeway, KMD, Kymco, Lance, Lifan, Linhai, Loncin, Longbo, Fuxin, Jiajue, Tao Tao, Tao Motors, Trailmaster, Maxtrade, Meitien, Motofino, Motorino, NST, Panterra, Panther, Qlink, Yiben, Red Streak, Redcat, Roketa, Schwinn, Strada, SYM, Tank, Terminator ,Tomberlin, TNG, United Motors, Vento, Vitacci, Wildfire, Wolf, X-Treme, X-Pro, Yongfu, ZNEN, Zhongneng , Zhilong, Geely, Wangye, ZH and more Manufactured by: Taizhou Zhongneng Motorcycle Co.; Jiangsu Zhongneng Motorcycle Co.; Jiangsu Meijunte Technology Co.; Taizhou Qianxin Vehicle Co.; Ningbo Dongfang Lingyun Vehicle Made Co.; Taizhou Zhilong Technology Co.; Zhejiang Jiajue Motorcycle Manufacturing Co.; Zhejiang Gelly Ming Industrial Co.; Taizhou City Senglong Motorcycle Manufacture Co.; Jiangsu Sacin Motorcycle Co.; Jiangsu Linhai Power Machinery Group Co.; Zheijiang TaoTao Vehicles Co.; Zhejiang Senling Motorcycle Co.; Sanmen County Yongfu Machine Co; Taizhou Jiaojiang Zhiwei Motorcycle Manufacture Co.; Huzhou Daixi Zhenhua Technology Trade Co.; Taizhou Zhongneng Motorcycle Co.; Zhejiang Riya Motorcycle Co.; Ningbo Longjia Motorcycle Co.; Taizhou Zhongneng Motorcycle Co.; and more