BPRATV Banshee 421 Stroker Big Bore Kit ARES 68mm Cylinders CP Pistons Cool Head

  

BPRATV Banshee 421 Stroker Big Bore Kit ARES 68mm Cylinders CP Pistons Cool Head. Yamaha Banshee 421cc stroker kit featuring ARES 68mm Nikasil cylinders, CP forged pistons and Cool Head. Built for pump gas power and reliability. Banshee 421cc ARES 68mm Athena-Style Stroker Big Bore Complete Engine Kit.

The BPRATV Banshee ARES 68mm Cylinder Kit is engineered for riders who want serious horsepower, long-term reliability, and unbeatable value. Featuring a factory pre-ported dune/play port design, larger water jackets, and triple exhaust ports, this kit is ready for +4mm stroker builds with no spacer required. Built to Perform - Complete 421cc Stroker Rebuild Kit. This complete top-to-bottom rebuild kit replaces higher-priced Athena cylinders with BPRATV ARES Nikasil cylinders that deliver true performance porting-not marketing gimmicks. Designed to compete directly with Cub-style builds, this kit can achieve 95+ HP on pump gas with proper tuning.

BPRATV ARES 68mm Nikasil cylinders - factory dune/play ported (ACTUALLY PORTED, no gimmicks). Triple exhaust ports with larger port windows for a wide, responsive powerband. Larger water jackets for superior cooling under high-load conditions. CP Carrillo forged STROKER pistons with rings, pins, and circlips. Complete heavy-duty aftermarket +4mm stroker crankshaft assembly with 115mm heavy-duty connecting rods. Please note: This kit does not include a Hot Rods stroker crankshaft; it features a high-quality heavy-duty aftermarket stroker crankshaft that we have tested and fully stand behind.

If you are specifically looking for a kit with a Hot Rods crankshaft, please see our other listings, as that option is also available. Heavy Duty wrist pin bearings. Special-cut 68mm big bore + 4mm stroker 22cc domes. Pro Design Cool Head with head stud kit and O-ring kit.

Cometic one-piece custom fiber base gasket and intake gaskets. Complete Yamaha Banshee engine gasket kit.

Complete Yamaha Banshee engine seal kit. Extra Components Included at No Additional Cost.

This kit includes critical extras that many sellers charge separately, ensuring your build goes together correctly the first time. BPRATV Talon Titanium Acorn Cap Nuts (Pro Design heads do not include nuts). Set of four new cylinder dowel pins - essential for any fresh build. New pair of NGK spark plugs for reliable first start-up. Port Timing Matters - Even on Pre-Ported Cylinders.

This 421cc kit is drop-in and bolt-on ready, and the cylinders are already factory dune/play ported. However, porting and port timing are not the same thing-and this is where many builds leave power on the table. Porting refers to the shape and flow characteristics of the ports (which is already done).

Port timing refers to when those ports open and close in relation to the crankshaft. When stepping up to a 421cc +4mm stroke, the piston travels farther, which changes the effective timing-even on a pre-ported cylinder. Cylinders are dune/play ported, but timing is optimized for 392cc-400cc setups. Correcting port timing restores ideal piston-to-port relationship for a +4mm stroke. Thick base gaskets only raise the cylinder and hurt compression and power.

Proper timing unlocks stronger mid-range, cleaner revs, and higher peak power. Use BPRATV's in-house port timing service to get everything this kit can deliver.

The Nikasil-plated aluminum cylinders provide superior durability, cooling, and piston life compared to traditional sleeves. Transfers heat more efficiently to keep engine temperatures lower. Harder, smoother piston surface reduces friction and wear. Longer service life between rebuilds.

Lightweight aluminum design improves throttle response. Proven across 392cc, 400cc, and 421cc Banshee builds. Athena vs CPI Cub vs BPRATV ARES.

Athena and CPI Cub cylinders have long been respected benchmarks in high-performance Yamaha Banshee builds. Athena is known for proven durability and consistency at a premium price point, while CPI Cub cylinders are recognized for race-focused power and Nikasil longevity. The BPRATV ARES cylinder bridges the gap-delivering Athena-level performance, strong power potential, and proven reliability with exceptional overall value for serious riders. Q: Are these cylinders actually ported or just triple exhaust?

A: TRULY PORTED - No Gimmicks, No Games. When we say ported, we mean it. Every cylinder is factory ported with a dune/play design that delivers hard-hitting mid-range pull and screaming top-end power for all-around performance. Don't be fooled by "Triple Ported" cylinder claims - all that means is the cylinder has three exhaust ports (ours do too). What sets us apart is that our cylinders are actually performance-ported for real gains, not just marketing jargon. Q: Can this kit compete with Athena or CPI Cub setups? The BPRATV ARES cylinders bridge the gap, delivering Athena-level performance and Cub-style power at a fraction of the cost. Q: Is race fuel required? You can use race gas with proper tuning and jetting but it's not required. Q: Is everything needed for a full rebuild included? This is a complete top-to-bottom rebuild kit that includes all the core components required for a proper 421cc setup. These are the main parts that are absolutely needed for a complete rebuild; however, we always recommend additional items depending on the condition of your motor-such as a new transmission bearing kit, new cylinder water plugs, billet water pump impeller upgrade, titanium clutch pusher, and many other optional upgrades and mods that are available.

At BPRATV, our promise is unwavering: The Best Parts. Every ARES kit is tested across real-world Banshee builds to deliver reliable, repeatable power. Trust BPRATV to keep your Yamaha Banshee running at its best, every single time. Upgrade your Yamaha Banshee with the ARES 68mm Cylinder Kit - power, precision, and reliability in one package! BPRATV - The Best Parts.

This product is exempt from emission standards under 40 C. DO YOU NEED THIS ITEM INSTALLED?

NOTICE REGARDING PHOTOS: Product photos used in our listings are for example only to show the high quality of our components. You will receive the correct quantity, size, and fitment of bearings, titanium fasteners, nuts, and bolts for the specific kit listed.

BEARING NOTICE: In some cases, you may receive SEALED bearings. If your application requires an OPEN bearing, the seals can easily be removed.

EMISSIONS & RACE USE ONLY: This product is exempt from emission standards and requirements of 40 C. § 1051 as provided by 40 C. § 1051.620, and California law e. Vehicle code §§ 27156 and 38391. BPRATV LLC shall not be liable for specific, incidental, or consequential damages (loss of property, equipment, profits, or revenue) resulting from sale, installation, or use of these parts.

This product is NOT DIY; we strongly recommend work be done by a qualified, experienced mechanic. Items installed or prepped (lubricated/sealed) are ineligible. Titanium Fasteners: Failure during use results in replacement only. INTERCHANGEABLE PARTS: We may substitute parts of equal quality from different manufacturers to prevent backorder delays. Prices and listings subject to change without notice.