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.