Crank Center Labyrinth Seal for Kawasaki KH Series (KH250/KH350/KH400) ,350SS– 4B/G Type | LABYRI™ by INOUE BORING

The biggest weakness of 2-stroke engines — center seal failure — has finally been solved with the LABYRI™ labyrinth seal.

※Labyrinth seal only – other components not included.

With LABYRI, you no longer need to worry about center seal blowout.
Thanks to its innovative non-contact metal design, LABYRI provides:

• ⚡ Zero energy loss

• 🚀 Sharp throttle response

• 🌀 Ultra-low resistance, free-spinning feel

Experience a significant improvement in pickup and performance —
LABYRI eliminates the risks while maximizing your engine’s potential.

Product Information

This is a fully original product developed by INOUE BORING.
The version shown here is for the 4-bearing crankshaft type.

At the heart of this product is our proprietary non-contact, all-metal labyrinth-style center seal — LABYRI™.

• ⚙️ Zero wear – Because it’s non-contact, there is no friction, and thus no mechanical wear over time.

• ⚡ Zero energy loss – The non-contact structure also means there's no rotational resistance, enabling smoother engine response.

• 🛠️ Durable, reliable, and built to last – Ideal for high-performance 2-stroke engines.

Trust LABYRI™ to eliminate the center seal issues that have plagued 2-stroke engines for decades — with no compromise.

🔧 Key Features & Selling Points

• ⭐ No other seal kits exist on the market for early-model SS350 — this includes both reproduction parts and labyrinth-type seals.

• 🔄 Allows you to convert the crankshaft of KH400, KH250, and SS400 (or mid-model SS250/SS350) to the low-friction early-model SS350 spec.

• 🧩 Reduces the number of main bearings from 6 to 4 — saving on bearing costs

• 🛠 No machining required on the crankshaft — bolt-on compatibility

• 🎯 Visually sharp design with crisp contours

• 🛡 Anodized surface finish for superior corrosion resistance

• 🧪 Inner shape faithfully matches the OEM spec as closely as possible

• 🎯 Inner bore is left unanodized to maintain precise dimensional tolerances

• ⚙️ Non-contact sealing means zero friction and smooth rotation

• 🪙 Full metal construction – no aging or deterioration like rubber seals

• 🚚 Shipping cost is displayed during checkout (flat-rate within Japan)

Proudly designed and produced by INOUE BORING – engineering precision for vintage 2-stroke engines.