H2 Billet Cylinder — EPISODE 3

You Feel It Immediately: “Quiet, Smooth, and Refined”

Kawasaki H2 (Mach IV / 750) is a legendary two-stroke triple.
In Episode 1 I shared why we started the billet H2 cylinder project, and in Episode 2 I explained the bridged port problem that Kawasaki triples have lived with for decades.

Now in EPISODE 3, I want to focus on the most important part: what you actually feel on the road.

One-Line Conclusion

“It becomes surprisingly quiet.”

It becomes surprisingly quiet.
Less vibration.
Smoother RPM rise.
And a refined mid-to-low acceleration feel.

Before “more power,” you notice higher quality. That is the first thing we heard again and again.

Why It Feels Smooth

Bridged Port Stability for Rings and Skirts

The logic is simple. On a two-stroke, large port windows can create instability.
But with a properly engineered bridged port, there is essentially no ring / piston-skirt “diving” into the port window.

When that instability disappears, the engine naturally feels smoother.
Less ring noise and less piston slap can change the character dramatically.

ICBM™ Keeps the Character Stable

Minimum Optimized Clearance That Lasts

With ICBM™, we aim for a bore condition that remains stable over time.
That means the minimum, optimized clearance can stay consistent — and that stability shows up as refinement.

This is not just about performance.
It’s about an engine you can live with — on hot days, on touring rides, and even when tuning is not perfect.

Real Rider Feedback

“It doesn’t feel like a Mach anymore.”

We heard the same reaction from multiple test riders:

“It doesn’t feel like a Mach anymore.”

Important Note (Top-Spec Test Bike)

Cylinder Effects Only

This test bike is a “top specification” H2.
Along with the billet cylinders, it also uses a billet head and a lighter clutch, etc.

Those parts contribute to the overall feel in other areas.
However, what we highlight here — quietness, reduced vibration, smooth RPM rise — are the cylinder-related changes.

The Unsung Hero — Plateau Honing

Crosshatch, Ring Seating, and Oil Retention

A quiet & smooth engine is not only design — finishing matters too.
One unsung hero behind this feel is plateau honing.

Plateau honing supports:

  • quick ring seating

  • oil retention

  • stable friction behavior over time

We see strong interest in plateau honing recently, so we will cover it more in the next episode.

FAQ

Q1. Can I get ICBM™ cylinder work for my Kawasaki triple?
Yes — in many cases we can help, but the best solution depends on model/year and cylinder condition. Please contact us with photos and your current bore size.
Q2. Knife-edge vs radiused bridge — what do you recommend?
For airflow behind the bridge, we generally prefer a radiused / blended shape rather than a sharp knife edge. It helps reduce separation and supports smoother flow.
Q3. Why isn’t the backside of the bridge mirror-polished?
Because it is very time-consuming. We focus our time on the areas that matter most for real-world durability and consistent performance.

 

View Product Collections Get a Quote
Looking for ICBM™ services or parts? Start here.

Next Episode Preview

Next time, I’ll share more about plateau honing and why it matters for long-term smoothness and durability.
(To be continued)

Back to blog