ICBM™: The Ultimate Wear-Resistant Coating for Engines
The Unending Battle Against Wear, the Silent Enemy in Your Engine...
Hello everyone, this is Sotaro Inoue from Inoue Boring. In my last article, I shared the big picture behind our ICBM™ technology—the passion that drove its creation and the potential it holds.
This time, I want to talk about one of the key benefits of ICBM™, a feature we have focused on and have the most confidence in: its incredible wear resistance.
Inside the cylinder, the heart of an engine, the piston withstands the full force of combustion and moves back and forth at furious speeds. This environment of high temperatures, high pressures, and constant friction means a silent enemy, wear, is always at work, slowly but surely eating away at the cylinder walls.
For over 70 years, we at Inoue Boring have been fighting this battle against wear. Our core business has always been restoring engines that have lost power, started burning oil, or developed strange noises due to wear, using the boring process to bring them back to life. But no matter how precisely we machined them, cylinders with conventional cast iron sleeves would eventually wear out again. For vintage motorcycle owners who love their bikes and want to ride them for years to come, this wear was a persistent and unavoidable problem.
We kept asking ourselves, "Isn't there a better way? Can't we free these amazing engines from the problem of wear?"
This long-held desire pushed us to develop ICBM™ technology. And now, we can say with confidence that ICBM™ is a technology that frees engines from the destiny of wear and gives them a durability that could be called a second youth.
Why doesn't ICBM™ wear out? How is it different from conventional thinking? And what future does it promise for your beloved motorcycle? Come and see the core of our passion and technology.
The Era of Cast Iron Sleeves and Their Limits: Why Wear Was a Given
First, let's look back at the conventional cast iron sleeve. To be clear, we are not dismissing cast iron sleeves. They are a great material and technology that supported 20th-century engine development and powered countless classic machines. We ourselves spent many years refining our skills in machining cast iron sleeves and exploring their potential.
Even so, cast iron had its limits as a material.
1. Its Inherent Softness
In the world of metals, cast iron is relatively soft. On the Vickers hardness scale (Hv), it measures only about Hv 80–140. In contrast, piston rings are often made of much harder materials, like hard chrome plating. When a hard material rubs against a softer one, the softer one naturally wears down first. This was the fundamental reason cast iron sleeves could not escape wear.
2. An Extremely Harsh Workplace
The inside of a cylinder is an incredibly harsh environment. Combustion temperatures reach several hundred degrees, explosion pressures can hit hundreds of pounds per square inch, and the piston moves back and forth thousands of times per minute. While lubricating oil helps, a sufficient oil film is not always present. Wear happens much faster during high-revving, high-load conditions when the rings are pressed hard against the cylinder wall.
3. The Unguarded Moment at Startup
Right after starting the engine, oil has not yet fully circulated, creating a moment when lubrication is at its worst. This is when metal-to-metal contact can cause microscopic damage known as scuffing. These cold starts, repeated day after day, cause wear to build up without you noticing.
4. The Limits of Improvement: The Contribution of Tufftride and What Lay Beyond
Of course, cast iron technology did improve. In the 1960s, special cast iron alloys like Tufftride appeared, which we were quick to adopt. This was a groundbreaking technology that improved wear resistance and sliding properties by modifying the cast iron's structure, contributing greatly to engine performance at the time. However, even with Tufftride, as long as the base material was cast iron, wear could not be stopped completely. It was simply "better for a cast iron," and still a long way from the "zero-wear cylinder" we were aiming for.
As people who have been in the engine machining business for years, we understood the limits of cast iron sleeves all too well. That is why we knew we needed a completely new approach—one that went beyond the framework of cast iron.
The Core of ICBM™ Technology: How the “Zero-Wear Cylinder” Was Born
Our work on ICBM™ technology started with a single goal: "to create a cylinder that does not wear." The key to this technology is a special composite plating (Nickel-Silicon Carbide) applied to the internal wall of an aluminum alloy sleeve or an all-aluminum block.
1. Unconventional Hardness
The most notable feature of this plating is its extreme hardness. The plating layer contains a high density of uniformly distributed, ultra-fine particles of silicon carbide (SiC), a material second only to diamond in hardness. These SiC particles have a Vickers hardness (Hv) of over 2000. To put that in perspective, the cast iron sleeves we discussed had a hardness of about Hv 80–140. It’s no exaggeration to say the difference is night and day. These super-hard particles withstand the harsh friction from the piston rings and prevent wear. The nickel matrix that holds the particles is itself around Hv 450, far surpassing cast iron sleeves.
2. The Ultimate Finish: The Craft of Plateau Honing
But hardness alone does not create the best sliding surface. For the final finish, ICBM™ uses a highly advanced internal polishing technique called "plateau honing." By precisely controlling the grinding stones and process conditions, we create a surface with deep, fine valleys (the cross-hatch) to hold oil while polishing the peaks (the plateaus) that the piston rings actually touch to a mirror-like smoothness. This method maximizes lubrication, optimizes the contact area, and reduces friction to an absolute minimum. This plateau honing process is where our years of experience at Inoue Boring come together—it is the domain of true craftsmanship.
3. Proven Durability: Zero Wear After 37,000 Miles?
We have conducted various tests to prove the durability of ICBM™ cylinders. In one long-term test, we installed a cylinder in a bike and ran it for 60,000 kilometers (over 37,000 miles). The results surprised even us. When we precisely measured the cylinder bore after the test, the amount of wear was within the margin of measurement error. In other words, we could not detect any meaningful wear, even at the micrometer (1/1000 mm) level. Honestly, it makes us wonder just how many hundreds of thousands of miles you would have to ride to find any wear at all. We believe this is the best proof that an ICBM™ cylinder has a potential lifespan far beyond that of a normal engine.
The Problems Caused by Wear: Why "Zero-Wear" Matters
Wear on the cylinder wall is more than just a part getting smaller; it is like a disease that quietly but surely degrades the performance and health of your engine. So, what specific problems does it cause?
1. Leaking Power and Poor Fuel Economy
As wear increases the gap between the cylinder and the piston rings, the high-pressure gas created during combustion leaks past them. This is known as blow-by, and it means the engine is losing compression—the very source of its power. The result is a drop in both power and torque. You might notice your bike doesn't accelerate like it used to or struggles on hills. Combustion efficiency also suffers, leading to worse fuel economy.
2. The Start of Unwanted Noise and Vibration
When the gap becomes too large, the piston can rock inside the cylinder, a condition known as piston slap. This causes an annoying "clattering" or "knocking" sound. Overall engine vibration increases, which not only makes the ride less comfortable but can also harm other components.
3. An Unwelcome Guest: Oil Burning and White Smoke
A worn cylinder wall prevents the piston rings from effectively scraping oil back down into the crankcase. This allows oil to enter the combustion chamber, where it gets burned. If you see white smoke from the exhaust or notice your engine oil level dropping unusually fast, you should suspect oil burning. This burned oil also leaves behind carbon deposits, which can cause further problems.
4. Beyond the Limit: Heat Fade and Engine Seizure
Increased friction from wear and poor contact between the piston and cylinder prevent heat from escaping properly. This causes engine temperatures to rise, leading to a drop in performance known as heat fade. In the worst-case scenario, this raises the risk of engine seizure, a fatal failure where the piston and cylinder get hot enough to melt and fuse together.
Wear affects every aspect of an engine and ultimately determines its lifespan. You cannot dismiss it as "just a little wear." This is exactly why the "zero-wear" characteristic of ICBM™ is so important for keeping an engine healthy for years to come.
The Benefits of ICBM™: Giving Your Engine a Lasting Youth
The incredible wear resistance of ICBM™ technology does more than just prevent your cylinder from wearing out. It brings immense benefits to your motorcycle and your life as a rider.
1. Is It Hard on Piston Rings?
Some people might worry, "Won't a hard plating wear out the piston rings?" You can put that concern to rest. In fact, the opposite is true. We have confirmed that because of its excellent low-friction and lubricating properties, an ICBM™ surface also dramatically reduces wear on the piston rings. It's not just hard; it's also smooth. It doesn't attack the opposing part—it protects it. This is one of the most unique and wonderful features of ICBM™ plating. By extending the life of both the cylinder and the rings, the two parts most prone to wear, the engine's overall durability is greatly improved.
2. Performance That Never Fades: A Like-New Feel, for Years
No wear means that the engine's optimal clearances, set when it was first assembled, are maintained for a very long time. This means compression does not drop, and the engine continues to deliver its original power, torque, and sharp response. You can enjoy riding in peak condition, almost as if the engine isn't aging. For us as engine builders, this is an ideal state.
3. Easier on Your Wallet: Freedom from Frequent Overhauls
A dramatic reduction in engine wear means the need for top-end overhauls becomes much less frequent. With conventional cast iron engines, an overhaul every few tens of thousands of miles was not uncommon, depending on how you ride. With ICBM™, you can expect many times that durability. As a result, you can significantly cut down on maintenance costs and effort. This is a huge advantage when maintaining vintage bikes, where parts and labor can be very expensive.
4. A Breakthrough for 2-Stroke Engines
A major reason we began serious development of ICBM™ was the wear problem in high-power 2-stroke engines like the Kawasaki H1 and H2 Mach. With their large exhaust ports, these engines were destined to suffer from severe cylinder wear because the piston rings would catch on the port edges. We used to face the frustrating reality that even after we bored a cylinder, it would quickly be ruined again. But the incredible hardness of the ICBM™ plating is strong enough to withstand even those port edges. This opened the door for riders to enjoy that thrilling 2-stroke acceleration and sound for much longer, and with peace of mind. I'll never forget the joy of that moment.
The wear resistance of ICBM™ is about more than just "making things less likely to break." By maintaining engine performance, reducing ownership costs, and solving problems that plagued certain models, it has the power to make life as a bike owner better and more secure.
Real-World Applications for Vintage Bikes: Bringing Legends Into the Future
The world of vintage motorcycles is where ICBM™ technology truly shines. Seeing classic machines that have fought against the "aging" process of wear get a new lease on life with ICBM™ is the greatest reward for our work.
Kawasaki H1/H2: Rev the Engine of a Legend Without Hesitation
Known by its nickname "Mach," the Kawasaki H1/H2 took the world by storm with its intense acceleration and triple-cylinder sound. But as a high-power 2-stroke, cylinder wear around the large exhaust ports was a constant headache for owners. The super-hard ICBM™ plating overcomes this structural weakness. It dramatically improves the durability of the port edges and reduces the risk of seizure. This allows owners to fully use the potential of that legendary, untamed engine without worrying about wear, and enjoy its thrilling acceleration and sound to their heart's content. This is the model we receive the most inquiries and happy feedback about!
Kawasaki Z1/Z2: Giving an All-Time Classic an Enduring Lifespan
The Z1 and Z2 hold a shining place in motorcycle history. After nearly half a century, however, many of them suffer from wear and loose original cast iron sleeves. Applying ICBM™ (by installing an aluminum plated sleeve) solves these problems at their root. The feedback from owners is full of joy and surprise: "The engine is amazingly quiet now," "The vibration is lower, making long trips easier," "It's so smooth, it feels like it could rev forever." This is the value ICBM™ provides—refreshing the heart of the Z with modern technology without taking away from its character.
Honda CB-F/R Series: The King of Air-Cooled DOHCs Roars Again
The CB-F/R series dominated the superbike scene of the 80s. While they are high-performance DOHC engines, they still face issues with compression loss and oil burning due to wear. By restoring the cylinders with ICBM™, these bikes regain their lost power, achieving a sharp throttle response and a stable idle. For owners looking to tune their engines further, the wear resistance and heat dissipation of ICBM™ are essential modifications for ensuring engine reliability.
Yamaha RZ/RZV, Suzuki GT/RGV-Γ: Legendary 2-Strokes, Back on the Front Line
As mentioned earlier, for 2-stroke machines with passionate followings like the RZ/RZV, GT series, and RGV-Γ, ICBM™ is a critical tool for maintaining their performance and lifespan. By reducing the risk of seizure and providing the strength to handle modifications like porting, it makes it possible to fully enjoy these exciting machines for years to come.
Beyond Borders and Displacements: Hope for All Engines
The application of ICBM™ is not limited to major Japanese models. We have the knowledge and equipment to handle a wide range of engines, from European classics like Ducati, Moto Guzzi, and BMW to small-displacement engines like the Honda Cub, as well as many other rare machines. Before you give up on an engine because parts are no longer available, please talk to us first. ICBM™ may be the solution that saves your beloved motorcycle.
As these examples show, ICBM™ is not a technology for just one type of bike; it is for any internal combustion engine that suffers from wear. We believe it is the ultimate restoration technology—one that doesn't just repair old parts, but restores an engine's original brilliance and gives it the strength to keep running long into the future.
Conclusion: Freedom from Wear and an Engine’s Lasting Brilliance
"Wear" has always been one of the greatest enemies of the engine, silently but surely ending its life. For years, we at Inoue Boring have fought this battle, and with ICBM™ technology, we have finally found a way to win.
The aluminum-plated sleeve, with its unconventional hardness of over Hv 2000, achieves an incredible level of wear resistance that is beyond compare with conventional cast iron sleeves. This allows an engine to maintain its original performance for a surprisingly long time, dramatically extending the overhaul cycles that have always troubled us. It even comes with the welcome bonus of reducing wear on the piston rings.
For vintage motorcycles especially, this "zero-wear" characteristic is invaluable. Your machine will be free from the many troubles caused by wear—compression leaks, oil burning, strange noises, and vibration. It will continue to have a youthful, powerful heartbeat, as if it has forgotten the passage of time.
Freed from the effort and cost of constant maintenance, you can enjoy more wonderful, worry-free hours with your beloved motorcycle.
The incredible wear resistance provided by ICBM™ technology is the key to giving an engine a lasting youth and brilliance. It is a powerful ray of hope for passing the engine culture we love on to the future.
Next time, I’m excited to talk about two other important aspects of ICBM™: lightweighting and low friction. How does making an engine lighter and smoother change the way a motorcycle rides? What kind of an advantage does that become, especially in sport riding and racing? I’m sure it will be a discussion that changes how you think about performance. Please look forward to the next article.
Thank you again for joining me as I share my passion for engines and ICBM™.
Sotaro Inoue
CEO, Inoue Boring Co., Ltd.