Yamaha Banshee 421cc Serval Cub Big Bore Top End Kit – 4mm Stroker (NEW)

Yamaha Banshee 421cc Serval Cub Big Bore Top End Kit – 4mm Stroker (NEW)

Regular price$1,999.99
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  • Turn your Banshee into a monster with this complete 421cc Serval Cub big bore top end rebuild kit. Designed for a 4mm stroker crank (115mm rods), this kit is packed with high-end components like titanium studs, billet domes, and coated pistons. No case mods needed—just bolt on and rip.


    ✅ What’s Included:

    • CPI Serval Cub Cylinder – 68mm bore x 58mm stroke (421cc)

    • Wiseco or Wossner Forged Pistons – 68mm Blaster-style

    • Nitride Coated Rings, Chrome Wristpins, Circlips

    • Billet Pump Gas Cool Head Domes

    • One-Piece Cub Base Gasket

    • Intake Gaskets

    • Cool Head O-Ring Kit

    • SKF Wrist Pin Bearings

    • Titanium Extended Cylinder Studs (no extenders needed)

    • Titanium Head Stud Kit w/ ARP 12pt Nuts – Lifetime Warranty

    • Water Jacket Plugs


    📦 Fitment:

    • Fits Yamaha Banshee 350 using a 4mm stroker crank (115mm rods)

    • No case modifications required

    • Compatible with stock or aftermarket bottom ends built for 421cc Cub/Serval configurations


    🛡️ Warranty Info:

    • CPI Cylinder Warranty: We’ll fix or replace any failed Cub cylinder not caused by misuse, break-in error, or improper installation.

    • Titanium Stud Warranty: Lifetime replacement if a stud fails during use (not installation). Studs must be returned for inspection.

    • General Warranty: Parts must be installed and tuned by a qualified, experienced builder. Warranty is voided by incorrect tuning, break-in, or assembly.

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