85 mm

**Engine Specifications:** - **Displacement:** 85cc with a 52mm bore and 40mm stroke - **Cylinder & Head:** One-piece design for improved power output, lower operating temperatures, and increased rider weight capacity - **Carburetor:** High-performance Speed carburetor for enhanced fuel delivery - **Reed Valve:** Controls air-fuel mixture for optimized performance - **Cylinder Lining:** Ceramic lining for durability, reduced friction, and lower operating temperatures - **Exhaust:** New ultra-quiet exhaust pipe with an oversized exhaust port - **Ignition System:** High-performance CDI using Yamaha components, paired with a performance magneto - **Fasteners:** Equipped with high-end stainless steel Allen bolts for added durability - **Additional Features:** Includes an improved gas cap **Complete Engine Kit Includes:** - **Engine:** 85cc 2-stroke engine with integrated cylinder and head - **Reed Valve Intake:** Enhances air intake efficiency - **Bearings:** Upgraded needle bearing for piston wrist pin and thicker crankcase with reinforced bearings - **Crankshaft:** Balanced crank with a stuffed crankcase, featuring a 40mm crank stroke for better power, efficiency, and reliability - **Piston:** Double window piston paired with a long 89mm rod - **Ports:** Large intake port with a 40mm bolt hole width and an oversized round exhaust port (28mm diameter, 60mm stud spacing) - **Mounting Studs:** Engine comes with larger 8mm x 1.25 engine mount studs - **Dimensions:** Engine measures approximately 9" x 9" x 5" **Mounting Kit & Accessories:** - **Ignition System:** High-performance CDI with Yamaha components - **Fuel Tank:** 2L black tear-drop gas tank, complete with a new fuel cap, fuel valve, fuel filter, and fuel line - **Chain:** Heavy-duty 415 chain with an included chain guard - **Chain Tensioner:** Ball bearing chain tensioner for smooth operation - **Muffler:** Ultra-quiet stainless steel muffler with sound insulation cotton inside - **Throttle Assembly:** Includes a gooseneck-style throttle cable, twist throttle, matching grip, and kill switch - **Clutch Handle:** Quick-release clutch handle for easy operation - **Mounting Options:** Large front mount to accommodate bicycles with large down tubes - **Sprocket Options:** Available with 36, 44, or 48 tooth rear sprocket - **Tools Included:** Spark plug socket tool and gear removal tool Compare with: phantom 85 motorized bike kit **Fuel/Oil Ratio:** - **Break-In Period (First 310 miles):** 20:1 - **Post Break-In:** 25:1