This Blue Line 39mm Cylinder Kit is a complete top-end rebuild for 50cc 4-stroke scooters running the 139QMB engine, the Chinese 50cc platform based on the Honda GY6 design. If your scooter is burning oil, losing compression, or just tired, this kit gives you a fresh cylinder, piston and rings plus the gaskets you need to put it back together in one order.
Features
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Complete top-end kit: Cylinder, piston, rings, wrist pin, circlips, dowel pins and gaskets in one box.
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Stock 39mm bore: Standard 50cc replacement size for 139QMB engines.
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Direct fit: Bolts on in place of the original cylinder with no modifications.
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Gaskets included: Head, base and intake gaskets come with the kit.
Specifications
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Part number: 1100-1501
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Alternate part number: 151-257
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Bore: 39mm
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Displacement: 50cc
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Overall cylinder height: 70mm
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Cylinder sleeve outer diameter: 44.7mm
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Engine type: 4-stroke, air-cooled
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Includes: Cylinder, piston, piston rings, wrist pin, 2 circlips, 2 dowel pins, head gasket, base gasket, intake gasket
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Brand: Blue Line
Model Fitment
| Engine Family |
Engine Codes |
| 139QMB (GY6 50cc) |
139QMB, 1P39QMB, YN139QMB, JJ1P39QMB, BD1P39QMB, BN139QMB |
| 139QMA (GY6 50cc) |
139QMA, 1P39QMA-2 |
| Common scooter brands |
Tao Tao, ZNEN, Peace Sports, Icebear, Jonway, Wolf, Baccio, Bintelli, BMS, Schwinn, SunL and other Chinese 50cc scooters |
Check the engine code stamped on your scooter before ordering. Engines marked with a listed 139QMA or 139QMB code may use this part, but verify the 39mm bore and 44.7mm sleeve diameter against your original cylinder.
Installation Notes
Clean all gasket surfaces thoroughly and install new gaskets. Follow a proper break-in period for the first few hundred miles.
