Polini Cylinder 50mm 81cc Nikasil Bore Kit w/Cast Piston Plus Weights (139QMB)
Description: Polini Cylinder 50mm 81cc Nikasil Bore Kit with Cast Piston Plus includes CVT roller weights for 139QMB 49/50cc 4-stroke engines. This increase in bigger bore displacement leads to an increase in performance and acceleration. The use of aluminum for this cylinder with coated chrome/nikasil plating offers superior durability and ensures very good cooling properties.
It’s also recommended to get a 50mm big valve head (Part# 1100-1239) in order to take full advantage of the bigger piston valve notch. However, you can use the original stock cylinder head without any problem.
When used in conjunction with a stock stroke of 41.4mm the engine displacement comes out to 81.3cc! When used with a 44mm stroker crank, engine displacement = 86.4cc!
Includes the following Cylinder, Piston + Rings, Gaskets (compression base gaskets, steel head gasket), Wrist pin, Circlips, Roller weights, and Variator slides.
• 1x Cast-Alumin Piston: 50mm
• 5x Piston Rings: 50mm
• 1x Wrist Pin w/C-clips: 38x13x9mm
• 1x Cast-Iron Nikasil Cylinder: 50mm
• Outer Sleeve Diameter 54.5mm
• Cylinder Height (w/o sleeve): 53mm
• Overall Height (w/sleeve): 70.3mm
• 6x Roller Weights: 16x13mm 5gm<9gm
• 3x Plastic Variator Slides
• Made in Italy
• Fit Intake Studs: M6 / Nuts: M6 / Socket: 8mm
• Fit Exhaust Studs: M6 / Nuts: M6 / Socket: 8mm
• Fit Rocker Arm Assembly: 64mm or 69mm / Feeler Gauge: .004in / .005in / Socket: 9mm
• Fit Cylinder Studs: 168mm 176mm / Nuts: M7 / Washers: M7 / Socket: 10mm
• Fit 50mm Stud Spacing /Diagonal 70.5mm
• Fit Cylinder Head 50mm 2V
• Fit Crankshaft 41.4mm to 44mm
• Fit Dowel Pin Set (8x14mm)
• Fit QMB 49/50cc+
Supported Models: GY6 139QMB 49cc-50cc 4-Stroke engines, Filly 50, Kymco 50, QLink 50, SYM 50, TaoTao 50
Item Weight & Package Dimensions:
• 2.869 pounds | 5.7” (L) x 5.7” (W) x 4.669” (H)