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

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.