Naraku 52.4mm Performance Cylinder (Incomplete) is designed for QMB139 50cc/49cc engines as a high-quality performance upgrade. This listing includes the cylinder only, along with piston, wrist pin, bottom gasket, and seals
SEE PHOTO FOR ALL INCLUDED PARTS
When paired with a stock 41.4mm stroke, this setup yields a displacement of 89.3cc, offering a noticeable boost in power and torque. When used with a 44mm stroker crank, displacement increases further to 94.9cc.
Ideal for those upgrading an existing top-end setup or replacing a damaged cylinder while retaining a performance piston and gasket package.
Features:
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Genuine Naraku Performance Cylinder (Incomplete)
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Includes: Cylinder, piston, wrist pin, bottom gasket, and seals
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Upgrades QMB139 engines from 49cc to 89.3cc (stock stroke) or 94.9cc (stroker)
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Compatible with short-style 64mm valves
Specifications:
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Bore: 52.4mm
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Outer Sleeve Diameter: 54.4mm
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Wrist Pin: 13mm
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Total Piston Height: 36.3mm
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Compression Height: 20mm (center of wrist pin to top edge of piston)
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Intake Valve: 23mm
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Exhaust Valve: 20mm
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Intake Port Diameter: 20.8mm
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Exhaust Port Diameter: 18.7mm
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Valve Style: Short 64mm Valve Stems
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Fits: QMB139 50cc/49cc engines (various makes/models)
Notes:
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Cylinder only (incomplete) – includes piston, wrist pin, bottom gasket & seals only.
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May require engine case modification to fit larger 52.4mm bore.
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Designed for use with non-emissions style heads.
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Not intended for use on public roads or land.
Compatibility:
