Athena 68mm 421cc Big Bore Stroker Kit - Yamaha Banshee
- Ships next business day
- 30-day hassle-free returns
- Call us: 541-668-7503
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✓ Fits
Yamaha Banshee YFZ350 (1987-2006). Complete 421cc big bore stroker conversion.
✓ The Only +4mm Stroker Athena Kit On The Market
This is a complete top-to-bottom motor rebuild that competes with the Cheetah Cub at a fraction of the cost. With proper tuning on pump gas you can easily hit 95+ horsepower. A true 421cc big bore stroker: 68mm Athena cylinders combined with a Hot Rods +4mm stroker crank for a massive jump in power over stock.
✓ What's In This Kit
- Athena 68mm big bore Nikasil-plated cylinders (pair)
- AZ Quad Parts designed Wiseco Pro Lite 68mm custom pistons (pair), includes pistons, rings, pins, and clips; forged aluminum with larger port windows for more power (piston weight only 7.5 oz)
- Hot Rods 4mm stroker crankshaft with 115mm heavy duty rods (trued and welded, ready to install)
- Pro Design cool head
- AZQP custom 21cc big bore domes (other sizes available on request)
- Cometic one-piece custom base gasket
- Wiseco heavy duty wrist pin bearings
- Athena oil seal kit
- Clutch cover gasket
- O-ring kit
✓ Choose Your Fuel
Select Pump Gas or Race Gas ONLY at checkout so your domes and compression are set up for the fuel you run. If you want a different dome size than the standard 21cc, contact us before ordering.
BUILT FOR SERIOUS POWER: This is a complete big bore stroker engine build for experienced builders or professional installation. Correct assembly, clearances, squish, jetting, and break-in are critical. Reach out to our shop if you want us to build it for you.
Ships fast!
📦 Shipping Information
In-stock items ship next business day. ModQuad parts dispatch Monday through Thursday.
Made-to-order and custom powder coat items show their lead time at the top of this page, right next to the truck icon. These are built fresh for you, so timing varies by brand and current backlog.
Need something by a specific date? Call us at 541-668-7503 before ordering and we will check stock and ETA on that exact part. We can often point you to an in-stock alternative from another distributor.
Questions? Contact us, we respond within 24 hours.
