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The Science of NOS and Tuning the Ultimate Drag Machine: Kawasaki ZX-14R Custom by Class4 Engineering

 11 min read

Class4 Engineering's ZX-14R

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This ZX-14R features a 340ps setup achieved by combining NOS with the stock 1441cc displacement. It competed in the JD-STER Pro Open class and secured 3rd place in the 2022 rankings. This bike serves as a valuable reference for 14R tuning, and its best ET in '22 was 8.742 seconds (1/4 mile ≒402.1m). In terms of rivals, much like production bikes, it faces off against the Suzuki Hayabusa. Mr. Yokota of Class4 Engineering explained to us the modifications that had been made to this machine. "This bike is also spec'd to produce 320ps. The displacement remains at 1441cc. The ZX-14R comes with a stock displacement of 1441cc and is equipped with a tuned head featuring a machined combustion chamber. Therefore, when compared to stock, it holds a power advantage of approximately 20ps over the Hayabusa. Additionally, this bike is fitted with CP-Carrillo pistons, Carrillo connecting rods, and chromoly cylinder stud bolts. We also implemented NOS (nitrous oxide supercharging) to ensure the engine can withstand the power output and transmit it more effectively. This approach holds true for both the Hayabusa and ZX-14R if you aim for faster times in drag racing.

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However, we have to be creative in what we do from there. In the case of the 14R, the cylinders are originally plated, making boring a challenging as they would need re-plating, which means the displacement cannot be increased. Additionally, there are no aftermarket high cams available, even if valve replacement is an option. Furthermore, the maintenance cycle is short. The Hayabusa requires maintenance once every two seasons, but with the 14R, once a season is mandatory, ideally even more frequently. And the crank metal should be checked frequently. Like any customization intended for street use, strengthening the engine oil and lubrication system is crucial for the 14R. We also reinforce the oil pump cover, as the stock casting is prone to distortion during rapid acceleration. Such distortion can impede proper oil flow, leading to potential seizing. Replacing it with a machined cover ensures greater strength, reducing the risk of distortion and leakage. We've also replaced the oil pump gear and oil relief valve, adding an original oil line to the crankcase side to prevent uneven oil distribution during rapid acceleration. The ZX-14R is high-tuned as is, and has a good access to the cylinder head, so we wanted to take advantage of that. However, it does require some effort to get to the bottom of it." The bike has also undergone porting and modifications to achieve higher speeds. Similar to the Hayabusa, the body has been modified to shed weight, lower the center of gravity, withstand increased power, and minimize resistance. Although it leans more towards drag racing, the engine and its components will be beneficial for those seeking rapid acceleration or extended distances. This is a project we'll be closely monitoring for its future records and the extent of work invested in it.

Electrical

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The meter, cockpit, and left and right master cylinders for the radial pump are stock components of the ZX-14R. However, the handlebar mounts are equipped with switches for adjusting the NOS system (blue on the left), A/F (air/fuel ratio, black on the right), and fuel injection (red on the right). The coil cord visible on the right is connected to the rider and activates the kill switch in the event of a fall.

Bodyworks

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The front cowl used to be the stock one that included lights, but now it has been replaced with a drag race-specific side cowl molded in a shape close to the stock design.

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The tail cowl has also been changed to a drag race-specific shape that follows the ZX-14R's stock design, and seat sponge and hip pads have been added.

Engine

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The engine is a 340ps spec. The combustion chamber was machined from the stock and the stainless steel valves and valve springs are also stock. The engine has been further modified with intake and exhaust ports to smoothly receive the supercharging pressure from the NOS system.

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Pistons are made by CP-Carillo with the same diameter as the stock φ84mm to ensure rigidity for NOS compatibility. The connecting rods are also Carillo H-rods, and the crankcase cylinder stud bolts are APE chromoly. The stock oil line was modified to prevent oil from seizing on the transmission side during rapid acceleration at the start of a race, which could lead to a blowout.

Chassis

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The upside-down front fork is a stock ZX-14R, and the ride height is adjusted using Brock's radial mount lowering tie-downs. The front brake system is also stock.

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The rear brakes have been removed here for safety reasons as well. The front and rear wheels are Brock's BST carbon with 3.50-17/6.00-17 sizes.

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The swingarm is an 8-inch long type manufactured by McIntosh in the U.S., and the rear shock is a Brock's EZ shock designed for a long wheelbase. These suspension parts, along with those for the Hayabusa, have become standard drag racing parts for Class4.

Gallery

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Specifications

Part Details
Engine CP CARRILLO φ84mm Forged Piston
CP CARRILLO H-shaped Cross Section Connecting Rod
APE Chromoly Stud Bolts
ROARING TOYZ Quick Clutch Access Cover
Exhaust BROCK'S PERFORMANCE Alien Head 2 Full System 14" Exhaust ZX-14R (12-23)
McINTOSH MACHINE & FABRICATION Aluminum Pro Swingarm
Wheels BST Diamond Tech 3.50-17 Front
BST Diamond Tech 6.00-17 Rear
Suspension BROCK'S PERFORMANCE Front End Lowering Strap
BROCK'S PERFORMANCE EZ Rear Shock
Drive System Neofactory EK NX Ring Chain 110
VORTEX RACING 840 Rear Sprocket 44T
Bodyworks CATALYST KAWASAKI ZX14 12'+ SUPERSPORT UPPER (Front Cowl)
CATALYST KAWASAKI ZX14 12'+ STOCK STYLE TAILS (Seat Cowl)

About Class4 Engineering

The price of the billet parts handled by Class4 Engineering are reasonable, and you can readily customize your beloved motorcycle. Their stylish parts are popular among Japanese fans as well as its homeland fans.

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Class4 Engineering brand page

Original Source of this Article

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Hakuyo
Hakuyo

editor

Hakuyo

A foreigner who rides in Japan, Japanese call this "Gaijin Rider". Third year in the Webike global team. He feels and shares the real bike life in Japan then presents you how interesting Japanese customs are.