I want to achieve the best bore machining! I want to make cylinders that don't lose weight! This is the motto of iB Inoue Boring in Kawagoe City, Saitama Prefecture. In gasoline engines, the number of plated cylinder models has been increasing more than cast iron sleeve models. In this case, the company thought that it should not continue to stick to cast iron sleeves. As a matter of fact, iB Inoue Boring has been familiar with the "plated cylinder technology" that applies special plating to aluminum sleeves since early on.
Modern engines are naturally plated cylinders
ICBM (Inoue Boring Cylinder Bore Mesot) refers to a special plating technique applied to the inner wall of an aluminum sleeve machined from aluminum muku material. Much of the material is brought to the recycler as swarf.
The "pillared" port is by far the most life-enhancing
The cylinders of the Kawasaki Triple H2/H1 are known for their powerful two-stroke engines, and even when bored and honed to perfection, abnormal wear can occur quite early (around 3,000 km!). In order to make more power, the ports had to be enlarged. As a result of making the ports too large for power, the piston rings and piston skirt would jump into the large intake and exhaust ports during reciprocating motion, causing excessive wear on the piston sleeve and piston ring edges. For such high-power-oriented 2-stroke engines, we developed a pillared ICBM with a "pillar" in the center of the intake and exhaust ports. This port pillar acts as a guide for the piston and piston rings, suppressing piston pivoting and enabling smoother reciprocating motion. The result is a quiet two-stroke engine that is virtually free of piston ring hammering and piston skirt slap noise.
This is a 500SS Mach III cylinder with a pillared ICBM. The pistons are genuine Kawasaki replica pistons from Shift Up's Dream Timer brand. The well-established pistons made by this company are available from STD size 025./050/075/100/The lineup extends to 125 oversize.
High-quality machining with high-performance CNC machine
The sleeve machining of the 2-stroke cylinder is performed using a horizontal machining center, and is machined according to program data. The position of the port holes and the shape of the dimensions are quantified by measuring the cylinder. Since the port holes on the cylinder side vary from manufacturer to manufacturer, the final finishing process is done by hand using a rheuter.
The 4-stroke cylinder is the ICBM of high durability
ICBM technology remains effective even in 4-stroke engines. On the Kawasaki Z2/Z1, the mating tolerances of the cast iron sleeves were lax and the material was beginning to deteriorate. With the reissue of the Z2/Z1 cylinder head as part of the original Kawasaki revival project, ICBM technology has become the focus of attention for the cylinder. The effects of ICBM cylinders are tremendous, with improved heat dissipation and reduced slip resistance, not to mention wear resistance. As with the Kawasaki H2 and H1, there are many examples of Z2 and Z1 applications. Of course, ICBM is also effective on the latest water-cooled engines, and the image above shows an example of ICBM used on a Suzuki Hayabusa along with bore up tuning.
Plateau honing technology should not be overlooked.
The cylinders used in ICBM are finished with plateau honing technology. The word "plateau" means "plateau". After finishing the deep oil reservoirs with a coarse diamond grinding wheel, the bore inner wall surface is finished to piston clearance with a special plateau honing wheel. This process is called "plateau honing" because the entire surface is finished like a plateau against a deep groove or valley. The plateau degree is measured by a surface roughness meter and delivered with the data attached.
- Point 1 - ICBM technology with overwhelmingly high hardness if you compare the hardness of the cast iron sleeve surface with that of the specially plated ICBM cylinder surface. Attention should be paid to the overwhelmingly high wear resistance.
- Point 2 - Special plating on aluminum sleeve provides high thermal conductivity and overwhelmingly lightweight compared to cast iron sleeve.
- Point 3 - Uniformity of the expansion rate reduces piston clearance and improves engine quietness.
- Point 4・ Because the hardness of the special plating is overwhelmingly high, the regeneration ability when the piston is seized is also high.
iB Inoue Boring has been in charge of mass production of genuine repair parts for Honda HRC's production racers RS250 and RS125, as well as the production motorcycle NSR250R. One of the main characteristics of the company is that it has already had experience in manufacturing "plated cylinders" since the 1980s in response to the needs of manufacturers. iB Inoue Boring had already experienced the merit of being able to offer the mass production processing technology cultivated over many years to individual users and shops by offering the "plateau honing technology". It has been more than five years since the company started to offer the plated cylinder technology to general users, and the ICBM technology is now recognized as the technology that can produce the highest quality cylinders among users who are interested in engine machining technology.
Unlike honing wheels for cast iron cylinders, ICBM cylinders are finished and delivered using a diamond honing wheel specially designed for plateau honing. To begin with, plateau honing itself is a high-level technology, but since it is standardized and a plated cylinder with overwhelmingly high surface hardness is used, the cylinder boasts overwhelmingly high performance.
As long as the bore diameter is 50mm or larger, any cylinder can be converted to ICBM, regardless of whether it is a 2-stroke or 4-stroke engine. Of course, not only the stock STD bore size, but also the big bore size is possible. In addition, even though the NSR250R uses plated cylinders, it is also possible to re-plate damaged cylinders. In other words, any cylinder from Φ50 up to Φ100mm can be converted to ICBM. However, it is not possible to convert cylinders made entirely of cast iron (cast iron block), such as old motorcycle engines.
Reaffirming the advantage of ICBM technology.
The first is "ultra-long durability". In measuring the hardness of the plating layer, when analyzed by the Vickers hardness measurement standard, the hardness of cast iron sleeves is 45 for soft ones and 140 for hard ones. On the other hand, the Pickers hardness of the plated cylinder manufactured by ICBM is 450, and by the way, when the Pickers hardness is measured for each process, the hardness is 450 during the preliminary nickel plating, and the silicon particles are mixed in the special plating for the final finish, and the particle hardness is 2000! Everyone can understand the overwhelming hardness. The silicon particles are at the forefront of wear until the end of the process, and even if the nickel base is slightly worn away, the silicon part is retained and the bore dimensions do not change.
Second, it is "lightweight". The weight of aluminum is about 1/3 of that of steel. This is an overwhelming difference when comparing sleeves alone. Since it is possible to reduce the weight of parts for the engine waist in kilograms, there is no doubt that it will have a great effect on the machine's mobility.
Third, high "heat dissipation" is also not to be overlooked. Compared to cast iron, aluminum sleeves have excellent thermal conductivity. This is a big advantage, especially for air-cooled engines.
Fourth, there is also "uniform thermal expansion". If you use a cast iron sleeve for an aluminum piston, you will have to maintain the correct piston clearance for the bore size due to the difference in thermal expansion. On the other hand, with aluminum sleeves, the coefficient of thermal expansion is close to that of cast iron sleeves, and the piston clearance can be reduced.
Fifth, there is the "resistance to seizure." iB has been receiving special plated cylinders for a long time, and it is not uncommon for an intact special plated wall to appear underneath the melted and stuck piston when lightly honing the cylinder bore that came in for re-plating. That is how strong the special plated cylinder is. As you can see, ICBMs offer a variety of advantages.
In cooperation with: iB Inoue Boring
