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BLACK SERIES YUMINASHI BIG BORE/STROKER GEARBOX ASSY (HONDA WAVE125/WAVE125i | DREAM125)

Brand : YUMINASHI

8.979,62₺
SKU:
23010-KPH-RZB
Availability:
Usually shipped out on Mondays & Thursdays (Except on Thai public holidays)...
Weight:
1.94 Grams
Minimum Purchase:
1 unit
Shipping:
Calculated at Checkout
Bulk Pricing:
View Details
buying-2-discount-300pxl-.png● "BLACK SERIES" YUMINASHI BIG BORE/STROKER GEARBOX ASSY (23010-KPH-RZB)

● Stop shearing your factory transmission teeth—and unlock your engine's true torque potential.

Building a high-performance big-bore or long-stroke engine is incredibly rewarding, but it places immense physical stress right on your factory drivetrain components. If you are pushing your bike with an aggressive cylinder kit or a 4-valve head conversion, you are operating on borrowed time with standard internals.

➠ You might have seen standard aftermarket replacement gears out there, but here is the cold engineering truth of the tuning world:
the stock Honda gear metallurgy was strictly calculated for a standard 10–11 Nm torque ceiling.

● When you massively increase displacement, that factory cast steel simply cannot absorb the severe shock loads.
The teeth strip, the components warp, and a broken gearbox can easily take down your entire crankcase assembly with it.

➥ That is exactly why we developed the "BLACK SERIES" Heavy-Duty Gearbox Assy.

‣ We engineered this assembly using elite, premium-grade hardened steel alloys specifically optimized to withstand extreme mechanical shear stress.
‣ We implemented a massive structural upgrade to the shift fork layout. By utilizing precision-thickened selector forks, this assembly completely eliminates physical fork deflection under hard, high-RPM foot pressure.
‣ You get absolute driveline security on your high-horsepower street or touring build, ensuring every bit of raw engine torque translates into forward momentum instead of transmission failure.

● Advanced Thermochemical Surface Technology:

The distinctive dark finish of the "BLACK SERIES" isn't just an aesthetic choice—it is a critical mechanical shield. Each gear wheel in this assembly undergoes an advanced thermochemical case-hardening process (nitrocarburizing).

This process diffuses nitrogen and carbon atoms deep into the outermost microscopic layers of the metal alloy, creating three massive performance advantages:

‣ Ultra-Hard Wear Layer: Drastically limits micro-pitting, scuffing, and fatigue wear on the gear teeth faces under severe operating temperatures.
‣ Reduced Friction Coefficient: Creates a smooth surface finish that facilitates slick, instantaneous "click" dog engagement for buttery smooth shifting.
‣ Enhanced Boundary Lubrication: The treated outer layer significantly improves surface oil-film retention, protecting your transmission meshes even during localized oil starvation or extreme racing loads.

● The Ultimate Anti-Detonation Load Recipe:

Many builders do not realize that your transmission geometry has a direct impact on how cool your engine runs. With fragile stock gears installed, severe heavy load spikes can induce massive localized cylinder heat and unwanted engine knock (detonation).
By upgrading to the race-grade metallurgy of the "BLACK SERIES", your transmission runs flawlessly with minimal mechanical binding. While this assembly perfectly retains the reliable, comfortable street drivability of your factory gear ratios, it optimizes power delivery to smooth out load transitions.

➥ Builder's Setup Tip:

To extract the absolute maximum speed and engine efficiency out of this assembly, we highly recommend pairing it with a Yuminashi 16T Front Drive Sprocket. This combination perfectly elongates your lower gears and transforms your 4th gear into a clean, close-ratio sports ratio that pulls hard up to top speed without dropping out of the powerband.

● Why your performance build needs the "BLACK SERIES":

● Heavy-Duty Metallurgy: Specifically case-hardened to cope with extreme big-bore and long-stroke torque loads without shearing teeth.
● Zero-Flex Shifting: Thickened, heavy-duty selector forks eliminate binding and missed gears under high-load pressure.
● Thermochemical Black Treatment: Vastly superior fatigue resistance, better oil retention, and lower friction coefficient compared to bare alloy alternatives.
● Perfect Street Geometry: Retains predictable OEM gear ratio spacing so your baseline sprocket calculations remain simple and comfortable for street or touring use.

budget-logo-2.png SMART SHOPPER TIP:
       ※ BUYING MORE THAN 1 PIECE CUT THE TRANSPORT PRICE, AND YOU RECEIVE A 10% DISCOUNT ON TOP OF IT!

   ※ B2B:  

  • Purchases between 2 & 4 pieces of this product will receive a 10% DISCOUNT 
  • Purchases between 5 & 9 pieces of this product will receive a 15% DISCOUNT 
  • Purchases between 10 & 19 pieces of this product will receive a 20% DISCOUNT 
  • Purchases between 20 & more pieces of this product will receive a 25% DISCOUNT

  • LOCATED IN THE USA | AUSTRALIA |  U.K. | EUROPE | PHILIPPINES? -WE PAY YOUR IMPORT TAX & IMPORT DUTIES!
    Click Here     if you would like to know if we are paying the import tax and import duties for your country!...

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