MXT Cylinder Head Standard 50 ccm AC 64 mm without SLS complete for GY6 4-stroke 139QMA / 139QMB / Hardware Store Scooter / Chinese Scooter / Baotian, Benzhou, Kymco

This cylinder head from MXT is a ready-to-install replacement cylinder head for 50cc 4-stroke engines of the GY6 type (139QMA / 139QMB), as they are widely used in import, hardware store, and Chinese scooters. Valves, valve springs, and valve stem seals are factory-installed and lapped - subsequent lapping or the use of special tools is not required.

Important Note:

• Before purchasing, compare the cylinder head with the original part installed on the vehicle using the product images, as vehicle-specific differences frequently occur in GY6 vehicles of this class.

Product Features:

• Ready-to-install cylinder head for GY6 50 ccm 4-stroke (139QMA / 139QMB) with pre-assembled valves, valve springs, and valve stem seals
• Version without SLS connection (secondary air system) - an existing SLS on the vehicle can be deactivated, which can have a positive effect on smoothness and torque
• Direct replacement for the stock cylinder head without lapping the valves before installation
• Rocker arm bridge and camshaft are not included in the scope of delivery - stock parts of the vehicle can be reused

Since valves and sealing elements are delivered fully pre-assembled, the laborious manual valve assembly is eliminated; the rocker arm bridge and camshaft from the stock vehicle can be reused, provided they are in perfect condition.

Technical Details:

• Product category Cylinder head
• Displacement 50 ccm
• Engine type GY6 4-stroke (139QMA / 139QMB, air-cooled)
• Version Standard, without SLS connection, complete with valves
• Valve length 64 mm
• Fastening 4-hole
• Manufacturer MXT

Vehicle and Model Compatibility:

• The cylinder head fits 50cc 4-stroke engines of the GY6 type (139QMA / 139QMB), installed in a variety of import and hardware store scooters from manufacturers Baotian, Benzhou, Jmstar, Jonway, Kreidler, Kymco, REX, Znen, Flex Tech, Huatian, Longjia, Motowell, Sachs, Tauris, Wangye, Xintian and others. Before purchasing, the cylinder head must be compared with the original part installed on the vehicle using the product images, as vehicle-specific differences may occur in GY6 vehicles of this class.

Assembly and Application Notes:

• The cylinder head is replaced directly with the stock cylinder head; the rocker arm bridge and camshaft from the stock vehicle are reused and must be checked for wear before assembly. Replace the cylinder head gasket during installation and adhere to the tightening torques according to the manufacturer's specifications. Check the valve clearance after assembly.

Note on Inspection Before Purchase:

• Before purchasing, compare the cylinder head with the original part installed on the vehicle using the product images, as vehicle-specific differences may occur in GY6 engines of this class.

About the Manufacturer MXT

MXT is the powerful private label of Heavy Tuned and stands for high-quality replacement and tuning parts for motorcycles, scooters, and geared mopeds.

As a reliable alternative to OEM parts, MXT offers a wide range of cylinder kits, carburetors, and crankshafts to variomatic components, fairing parts, and batteries. The products impress with solid workmanship, precise quality, and a strong price-performance ratio.

Ideal for riders looking for durable replacement parts and tuning parts for many vehicle models.