Precision Geometry for Every Rider: KAWASAKI GPZ900R Custom by MC GEMMA

MC GEMMA's GPZ900R

MC Gemma has modernized the GPZ900R Ninja by updating its stock dimensions (early models had 16- and 18-inch wheels, while later ones had 17- and 18-inch) to accommodate 17-inch tires front and rear. To achieve this, they offer the “JCG-N” frame modification, which mainly lowers the swingarm pivot.

The process involves adding material under the swingarm pivot of the stock steel diamond frame to maintain strength, then lowering the pivot by 20mm. Precision drilling ensures the frame remains level and square to the bike’s direction of travel. At the front, the engine hangers are reinforced by welding collars through the mounting holes without deforming the hangers, improving both clamping reliability and post-installation rigidity. Optional adjustments for the shock mount position are also available, and additional reinforcements can be tailored to the owner’s riding style, allowing each bike to fit its rider perfectly.

This black, gray, and pink bike features a JCG-N frame with options, as well as a swapped engine. The compact cylinder head cover reveals the change. According to Mr. Ishida of MC Gemma: “We started with a ZZR1200 engine. Since the ZZR uses downdraft intake, we swapped the cylinder head for a horizontal intake head from a ZRX1100. The ZZR has a stock 6-speed transmission and a higher compression ratio, which are advantages. The frame uses full-option JCG-N, and the shock mount position is adjusted with a machined attachment. This isn't just a modification in the stock position, but rather, it moves the upper mount to the ideal location. The stock rear suspension tends to rise sharply and stiffen when carrying two riders, but this setup softens that characteristic, allowing smooth movement throughout the entire stroke." This optional setup highlights the depth of customizations available. The engine also retains the 6-speed transmission from the Ninja, while the increased displacement adds more torque.

This bike demonstrates that rideability can also be achieved with a different engine approach. All parts that the rider comes in contact with are adjustable, a feature common to all the shop’s demo bikes. The seat is an MC Gemma SLS model with the “high seat” option, 20mm higher than the standard +10mm, to suit the owner’s body size.

Ishida, who considers the JCG-N frame to be the heart of the shop's customs, has a personal project in mind: creating a lightweight Ninja with a stock look using a JCG-N frame. Returning to the original appearance but keeping it light. He plans to build one first and enjoy the results for himself.

While part selection requires careful thought, Ishida clearly has a wide range of options. From the engine setups and frame modification choices to the 1108cc Ninja head builds, he has many tricks up his sleeve. The final result—a stock-look Ninja on a JCG-N frame—is a bike that anyone would be eager to see.

Handlebar

The front end uses a K-FACTORY Type 2 triple tree with adjustable fork offset, paired with adjustable clip-on handlebars. The meters are arranged on a custom panel: from the left, there’s a DAYTONA VELONA digital speedometer (φ60), a Stack ST200 tachometer, and a Stack ST3200 fuel meter, with a Yoshimura PRO-GRESS 2 multi-temp meter below. On the top right, a Protec shift position indicator is also visible. Both left and right master cylinders are GALE SPEED VRC.

Bodywork

The seat has been upgraded to an MC GEMMA SLS high seat. On top of the standard “stock +10mm” height, an additional +20mm was added to suit the owner’s build.

Engine

The engine combines a ZZR1200 1164cc unit with a ZRX1100 horizontal intake head to maximize torque. The radiator has been enlarged, and titanium water pipes from K-FACTORY are used. For the frame, it is equipped with a K-FACTORY down tube and riding steps designed to fit a 20mm lower pivot position.

The carburetor is an FCR φ39mm with a sponge filter. The horizontal intake head is for a ZRX1100, with fins and red wrinkle paint on the head covers.

Chassis

The front forks are Ohlins RWU, with front brakes consisting of Brembo axial 4-piston calipers and SUNSTAR Premium Racing discs. The wheels are MAGTAN JB4, replacing the stock 3.00-17/3.50-18 with 3.50-17/6.00-17 front and rear.

At the rear, a Brembo P2-RS84 caliper is paired with a SUNSTAR Premium Racing disc. The exhaust system is a K-FACTORY CLR-RG Exhaust II with a hexagonal silencer. The shock mount position has been adjusted using optional JCG-N frame modifications.

The swingarm is K-FACTORY’s new large double-beam reinforced cross-section design, combined with an original link from the JCG-N frame options. It’s fitted with an Ohlins shock for the 17-inch Ninja (KA203), and the drive chain is a D.I.D 520ZVMX.

Gallery

Specifications

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